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Kinetic vs. thermodynamic control of β-functionalized cyclic ketones: a theoretical investigation of regioselective formation of enolates

Kinetic vs. thermodynamic control of β-functionalized cyclic ketones: a theoretical investigation of regioselective formation of enolates
Manuel Petroselli* and Corrado Bacchiocchi
Org. Chem. Front., 2022, 9, 6205-6212
https://doi.org/10.1039/D2QO01343F

Thermodynamic- and kinetic-controlled deprotonation of symmetric and asymmetric ketones is a well-known process that leads to the formation of enolates, one of the most important intermediate in organic chemistry. Regio-selective deprotonation assumes extreme importance, being critical to the success of organic reactions, when unsymmetrical carbonyl compounds such as ketones, having α-hydrogens in both sides, are taken into account. To the best of our knowledge, no studies have specifically reported on β-functionalized ketones in which regioselective formation of enolates could be less obvious and intuitive with respect to that observed in the most familiar α-functionalized analogues.

Figure 1. Chemical structure of ketones 1–6 involved in this study (A). Potential thermodynamic (4–6a) and kinetic enolates (4–6b) from the deprotonation of 4–6 using LHMDS (B).

Here we report a theoretical study at the DFT level of theory on a group of β-functionalized cyclic ketones 1–6 (Figure 1) to shed light on kinetic parameters (e.g., electronic effect and steric hindrance) and any other parameters (e.g., non-covalent interactions) related to the formation of kinetic and thermodynamic enolates through the use of hindered and strong bases, such as LHMDS and KHMDS. These bases have been taken into account as models to investigate the effect of counter cations (Li+ or K+) on the enolate formation process.

Surprisingly, “thermodynamic enolate” 4a was obtained as single product under kinetic conditions (THF, −78 °C) while ketone 5, gives “kinetic product” 5b as main enolate under same conditions with a regioselectivity of 70 : 30 over the “thermodynamic product” 5a. The unusual behavior reported in the literature for ketones 4 and 5 in the presence of LHMDS captured our attention and fed our curiosity.

Figure 2. Conformers and relative stability from Li-enolates from ketone 4. Relative stability for each Li-conformers is reported in kcal/mol in parentheses. Hydrogens have been hidden for better clarity.

A conformational study on the Li+@4 complex highlights the coordination ability of the functional group in β-positon (e.g. aldehyde group) and unveils its effect on the resulting enolate distribution (see Figure 2).  The lack of functional groups with coordination ability in 13 does not allow the double coordination of Li+ cation and consequently, no alteration of the enolate distribution is observed when (Me3Si)2was exchanged with LHMDS. The observed effect must be attributed to the coordination ability of the functional group (e.g. aldehyde in 4, cyano in 5 and nitro group in 6) and their directionality. Aldehyde and nitro group in 4 and 6, respectively, showed a superior directionality compared to cyano group in 5, leading to a higher stabilization of the relative TS for the presence of Li+ or K+ cations and consequently, higher regioselectivity towards “thermodynamic enolate” as experimentally reported (Table 1).

Table 1 Activation energy (Ea), ∆EEa and ∆∆EEa for ketones 4–6 in the presence of Li+ and K+.

On the other hand, the linear orientation of the cyano group (–C≡N) in 5 does not allow a proper coordination with the Li+ cation, showing a ∆EEa of 0.7 kcal/mol and leading us to suppose the presence of both enolates (5a and 5b) in the resulting solution (see Table 1 – Entries 5 and 6) as reported in literature. However, higher regioselectivity towards the “thermodynamic enolate” 5a is detected in presence of KHMDS where a ∆EEa of 4.9 kcal/mol is now observed (see Table 1 – Entries 7 and 8). This is rationalized by the better coordination between K+ cation and cyano group derived from the bigger size of the K+ cation with respect to the Li+ cation (Figure 3), highlighting how preliminary base selection (e.g., LHMDS vs. KHMDS) could strongly affect the resulting enolate distribution.

Figure 3. Comparison between thermodynamic enolates 4a (A), 5a (B) and 6a (C) coordinated to Li+ (left) and K+ (right).

We believe this work: (i) sheds light on the kinetic parameters that affect the regioselectivity in β-functionalized cyclic ketones, (ii) gives reasonable explanations for the unusual regioselectivity reported in the literature for some β-functionalized cyclic ketones such as 4 and 5, and (iii) could be a source of inspiration for future regioselective synthetic approaches and promotes the use of non-covalent interactions in the field of stereochemistry.

Corresponding author:

Dr. Manuel Petroselli 
ETH Zürich
Manuel Petroselli received his Ph.D in 2017 from Politecnico di Milano. From December 2017 to January 2020 he did postdoctoral studies in the Rebek Group at the Shanghai University and from March 2020 at ETH Zürich. The research field of Dr. Manuel Petroselli is supramolecular chemistry with a particular interest in radical processes and the study and development of water-soluble dynamic systems for biological applications.
ResearchGate: https://www.researchgate.net/profile/Manuel-Petroselli
Twitter: @manu_petros
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Organic Chemistry Frontiers Best Covers of 2023

We are proud to announce the three best covers of Organic Chemistry Frontiers in 2023! The awarded works were chosen by our readers through a worldwide vote. To learn more about the science behind the winning pieces, read the cover articles below for free until 29 February 2024. 

Ligand-assisted olefin-switched divergent oxidative Heck cascade with molecular oxygen enabled by self-assembled imines

Bairong Liu, Jianhang Rao, Weibing Liu, Yang Gao, Yanping Huo, Qian Chen and Xianwei Li *
Org. Chem. Front., 2023, 10, 2128-2137

 

Photo-induced nickel-mediated cross-electrophile coupling for alkylated allenes via electron donor–acceptor complexes

Zhao-Zhao Zhou,* Xiao-Feng Zhai, Shu-Liang Zhang, Ke-Jian Xia, Haixin Ding,* Xian-Rong Song, Wan-Fa Tian, Yong-Min Liang and Qiang Xiao *
Org. Chem. Front., 2023, 10, 298-303

Org. Chem. Front., 2023, 10, 1817-1846

 

Congratulations to the winners!

We would like to express our sincere appreciation for all the support and contribution from our authors, reviewers, and readers during 2023.

Looking forward to receiving your high-quality work in 2024.

Happy New Year!

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Organic Chemistry Frontiers Early Career Advisory Board – Open for Nominations

We are delighted to announce the establishment of our inaugural Early Career Advisory Board at Organic Chemistry Frontiers. This initiative aims to provide a direct channel for engaging with early-career researchers, supporting their professional development, and infusing our journal with fresh innovative perspectives from the younger generation.

We warmly invite you to nominate an emerging investigator to the board or encourage your colleagues to self-nominate before 30 November 2023.

Role of the Early Career Advisory Board

At Organic Chemistry Frontiers, we value the voices of early-career researchers. Joining the board, you will be part of a dynamic group of emerging investigators, helping shape the future of a leading organic chemistry journal and benefiting from networking opportunities with the journal’s Editorial and Advisory Board members.

Your insights will be invaluable as you provide feedback on the journal’s scientific standards, suggest emerging topics and researchers worth featuring, and contribute to promotional and visibility initiatives within your community.

Terms of Service

Normally, members of the Early Career Advisory Board will serve a term of two years, with an option for reappointment for a maximum of two consecutive terms.

Eligibility

  • Nominations are open to researchers of any nationality from academia or industry.
  • Candidates must be no more than 5 years from starting an independent research position (Assistant Professor or industry equivalent); appropriate consideration will be given to those who have taken a career break, followed a different career path or work in systems where their time period to independence may vary.
  • Candidates should demonstrate a commitment to advancing organic chemistry through developing high-quality journals.

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Please email the following information to OrgChemFrontiersED@rsc.org for your nominations before 30 Nov 2023.

Self-nominations are very welcome. If you are interested in joining our Early Career Advisory Board, please provide:

  • An up-to-date CV which highlights your engagements in academic activities (conferences participation) and services to the wider community (journals, societies, etc.)
  • Any supplementary materials, such as a brief supporting statement from an active Principal Investigator or contact information of references

To nominate someone else, please provide:

  • Candidate’s name, position, affiliation, website URL and contact details, along with a brief description of the candidate’s research contribution and community engagement
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It is suggested that you should get the nominee’s consent before submitting the nomination.

Selection Criteria

Editorial Board of the journal will consider the following aspects of all nominations as appropriate:

  • Profile within institute and/or community
  • Involvement in community and advocacy activities
  • Area and quality of research
  • Motivation to join Early Career Advisory Board

We look forward to receiving your nominations!

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Emerging Investigator: Chuan He at Southern University of Science and Technology

Emerging Investigator: Chuan He

Position          Associate Professor

Postdoc          2013–2017  University of Cambridge

Education       2008–2013  Wuhan University          Ph.D.

                       2004–2008  Wuhan University          B.Sc.

Group website        http://faculty.sustech.edu.cn/hec/en/

ORCID                    0000-0002-9983-7526

Read Chuan He’s Emerging Investigator Series article in Organic Chemistry Frontiers and learn more about him.

     
  Stereodivergent asymmetric synthesis of P-atropisomeric Si-stereogenic monohydrosilanes  

 

We herein report an efficient one-pot strategy for the stereodivergent asymmetric synthesis of various P-atropisomeric Si-stereogenic monohydrosilanes with excellent stereoselectivity from dichlorosilanes.

 

  From the themed collection: OCF Emerging Investigator Series  
  The article was first published on 23 Aug 2023  
  Org. Chem. Front., 2023, Advance Article  
  https://doi.org/10.1039/D3QO01084H  
     

My research interests

Key words: chiral organosilicon chemistry, chiral organoboron chemistry, asymmetric catalysis, synthetic methodology, chiral organic materials
My current research interests focus on chiral organosilicon and chiral organoboron chemistry, particularly aiming to develop new synthetic methods to expedite the syntheses of silicon-stereogenic silanes and boron-stereogenic compounds with high efficiency and selectivity, and to explore their applications in asymmetric catalysis, chiral materials, and chiral bio-active molecules. 

10 Facts about me

The most exciting thing about my research is pushing the frontiers and breaking the boundary of chiral materials.

The next big goal of my research is to explore the unique functions and applications of these non-natural chiral organosilicon and boron molecules.

My biggest goal as a researcher is to precisely manipulate atoms to form any molecules as one would wish.

My favourite academic article is always the next one.

If I were not an organic chemist, I would be a designer or director.

The best advice I have ever been given: always take the high road; be adventurous, be bold, but savor it.

I advise my students to work hard, play harder, and dream even more.

My favourite place on earth is Cambridge, UK.

In my spare time, I enjoy traveling, watching movies and Premier League.

Guaranteed to make me laugh is watching Stephen Chow’s movies.

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Emerging Investigator: Michael C. Young at the University of Toledo

Emerging Investigator: Michael C. Young

Position          Associate Professor

Postdoc          2014–2016  University of Texas at Austin

Education       2009–2014  University of California, Riverside          Ph.D.

                       2006–2008  Western Carolina University                   M.Sc.

                       2003–2006  Western Carolina University                   B.Sc.

ORCID            0000-0002-3256-5562                      Google Scholar

Read Michael C. Young’s Emerging Investigator Series article in Organic Chemistry Frontiers and learn more about him.

     
  Oxidative Mizoroki–Heck reaction of unprotected cinnamylamines at ambient temperature under air  

 

Cinnamylamines make-up many important drugs that target G protein-coupled receptors.

 

  From the themed collection: OCF Emerging Investigator Series  
  The article was first published on 04 Jul 2023  
  Org. Chem. Front., 2023, 10, 3982-3988  
  https://doi.org/10.1039/D3QO00778B  
     

My research interests

Key words: sustainability, organometallics, drug discovery, catalyst design, synthetic methodology
Michael Young’s research focuses on developing new synthetic methods to expedite chemical synthesis of biologically active molecules. A unifying theme of his group is to incorporate sustainability in everything they do, either through developing more efficient chemical processes, reducing the use of hazardous reagents, or developing more active catalysts. His group is interested in everything from designing new catalysts, to demonstrating their synthetic utility, to collaborating to determine the activity of all newly developed compounds with a particular focus on treatments for opioid use disorders. 

10 Facts about me

When I was a kid, I already wanted to become a researcher, though my first interest was in brain-computer interfaces.

If I weren’t a scientist, I’d probably be a musician, specifically a composer/performer. My favourite instrument is the F horn.

I try to impress upon my students the value of creating and exploring their own research ideas and interests as students. Graduate school may not be the best compensated time, but it is the freest to explore new ideas.

If I could go back to graduate school, I would work with someone in the directed protein evolution field. Biocatalysis can do so many cool things that synthetic chemists are trying, but mostly failing, to replicate.

My favourite reaction is the Ireland-Claisen rearrangement. It helped me to solve a challenging product synthesis that I could not achieve through other means.

My favourite metal is molybdenum, even though we don’t work with it at the moment.

My favourite book is Brave New World by Aldous Huxley. I enjoy dystopian literature, although perhaps less as some of these works begin to feel more prescient than fictitious.

I enjoy listening to video game sound tracks. I find it helps to focus while I’m writing grant proposals or manuscripts.

I am happiest when I am surrounded by mountains.

My biggest goal as a researcher is to do something so off-the-wall that my group earns an Ig Nobel Prize.

Click to find out our Emerging Investigators and their work

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Oxidative Mizoroki–Heck reaction of unprotected cinnamylamines at ambient temperature under air

Oxidative Mizoroki–Heck reaction of unprotected cinnamylamines at ambient temperature under air
Olutayo N. Farinde, Vanaparthi Satheesh, Kendra K. Shrestha, Carmen R. Rhinehalt, Vinod G. Landge and Michael C. Young
Org. Chem. Front., 2023, 10, 3982-3988
https://doi.org/10.1039/D3QO00778B

Cinammylamines and 3,3-diarylallylamines represent an important class of molecules for drug discovery, and can serve as intermediates thanks to their olefin functionality which can lead to further elaboration. However, there are numerous challenges in the application of organometallic methods to synthesize highly-functionalized 3,3-diarylallylamines. Historically these reactions required protecting groups, with the protecting group both limiting substrate decomposition as well as improving regioselectivity by imparting a directing effect (Scheme 1a). Recent efforts have established feasibility for direct free amine-directed reactions that avoid the need for protection and deprotection, but which suffer from selectivity issues due to the presence of different Pd species which promote different reaction pathways (Scheme 1b). Notably, β-protio allylamines undergo both Heck reactions to give trans-functionalised products as well as C–H activation to give the cis-functionalised products as mixtures. Meanwhile, β-substituted allylamines preferentially undergo a γ,γ’-diarylation reaction rather than the simple γ-monoarylation due to the reactivity of the in situ-formed Pd nanoparticles responsible for the reaction.

To solve the stereoselectivity challenge, the group of Prof. Michael C. Young at the University of Toledo has unveiled a new protocol for selective Mizoroki–Heck arylation of unprotected cinnamyl and allylamines (Scheme 1c). Compared with previous work, a pivotal change was to exploit an oxidative Heck reaction using aryl boronic acid as the coupling partner. By using the aryl boronic acid, the conditions could be made sufficiently mild to essentially shut down the C–H activation pathway, giving >20:1 selectivity in most cases.

Scheme 1. Approaches for the Mizoroki–Heck reaction of allyl and cinnamylamines.

The researcher team demonstrated the broad applicability of their approach by successfully synthesizing a range of unsymmetrical 3,3-diarylallylamine derivatives with overall good structural diversity. The method presented by the research team not only improves the overall synthetic process but also offers a pathway to access a wider range of drug molecules in a more cost-effective manner. By comparing their reimagined Mizoroki–Heck reaction with existing methodologies utilizing protected amine substrates and aryl iodides, the researchers highlighted the numerous advantages of their approach. With improved atom and step economy, higher selectivity, and broader substrate scope, their method represents a significant advancement in the field of organic synthesis.

Scheme 2. Substrate scope of aryl boronic acid coupling partners in the E-selective Mizoroki–Heck reaction on cinnamylamines. Reactions were performed using amine (0.15 mmol) and aryl boronic acid (0.30 mmol) under air atmosphere. All reactions were performed in triplicate and the average isolated yields reported. E/Z ratios were determined from the crude 1H NMR using 1,1,2,2-tetrachloroethane as internal standard. a Solvent was 0.9 mL HFIP:0.3 mL AcOH. b Solvent was 4.0 mL AcOH. c Reaction was performed under 1 atm of O2.

The researchers examined electron-deficient carbonyl-containing compounds with various functional groups, such as esters, ketones, aldehydes, amides, and nitriles (Scheme 2). The reaction proceeded successfully for all these compounds, and the nitrile group remained intact without undergoing hydrolysis, unlike in previous harsher conditions using a different coupling partner. The reactions generally exhibited high E-selectivity, with the Z-product undetectable in several cases. The researchers also explored electron-poor substrates containing fluorides and bromides, although the bromide compound had a lower yield. The recovery of the starting amine was reasonably high, and analysis revealed that the low yield of the bromide compound was due to a complex mixture of products resulting from Suzuki-Miyaura cross-coupling. Conjugated systems and electron-rich groups on the arene were also compatible with the reaction. Additionally, a coupling partner with both electron-withdrawing and donating groups yielded the desired product without the formation of the Z-isomer.

Scheme 3. Substrate scope of cinnamylamine coupling partners in the E-selective Mizoroki–Heck reaction on cinnamylamines. Reactions were performed using amine (0.15 mmol) and phenyl boronic acid (0.30 mmol) under air atmosphere. All reactions were performed in triplicate and the average isolated yields reported. E/Z ratios were determined from the crude 1H NMR using 1,1,2,2-tetrachloroethane as internal standard. a Solvent was 0.9 mL HFIP:0.3 mL AcOH. b Solvent was 4.0 mL AcOH. c Reaction was performed under 1 atm of O2.

In the investigation of amine substrate scope, various secondary amines were found to be viable substrates (Scheme 3). This included secondary amines with α-tertiary, α-secondary, and α-primary aliphatic substituents. Although cyclopropylamine showed low reactivity, introducing a methylene spacer enabled the generation of a reactive substrate. When targeting the addition of phenyl groups to the substrate, a spot check revealed a strong preference for the E-product over the Z-product (>20:1 ratio) when using 4-ethoxycarbonyl phenylboronic acid as the coupling partner. Sterically congested bornylamine derivatives, aliphatic amines with aromatic or heteroaromatic groups, and saturated heterocycles such as tetrahydrofurfuryl could also be successfully converted to the desired products. Similar E/Z-selectivity was observed when using 4-ethoxycarbonyl phenylboronic acid as the coupling partner for these substrates. Amino acid-derived substrates yielded good yields of the product, with complete E-selectivity observed based on the crude reaction mixture’s 1H NMR. The stereochemistry of the amino ester was confirmed to have >99% enantiomeric excess (ee) based on Mosher amide analysis. Electron-rich furfurylamine-derived substrates were viable, whereas pyridines did not show reactivity. N-tert-butyl-(4,4-dimethylamino)cinnamylamine, which decomposed under previous harsh conditions, could be converted to the desired product under the milder conditions, albeit with decreased Z/E-selectivity. Furthermore, an amine derived from podophyllotoxin, containing several oxygen-based functional groups, successfully participated in the reaction. Control of β-hydride elimination was achieved when a 3-(phenethyl)-substituted allylamine was used, resulting in the formation of the β,γ-unsaturated allylamine product. Expanding the scope to less and more-substituted substrates, primary cinnamylamine was functionalized with the desired product in 68% yield. The need for CO2 to prevent amine decomposition during the reaction, as in previous work, was not necessary under the milder conditions. Acyclic and cyclic amine substrates could be functionalized with good yields, demonstrating the versatility of this modified approach to amine functionalization. Trans-selectivity was observed when unsymmetrical 3,3-diarylallylamines were used as substrates.

Figure 1. Proposed catalytic cycle.

Young and his coworkers propose a preliminary mechanistic understanding of the Mizoroki-Heck reaction using aryl boronic acids as coupling partners (Figure 1). They suggest that the active catalyst is formed through the incomplete reduction of Pd(OAc)2 to Pd nanoparticles (NPs) ligated by allylamine. Transmetallation with activated aryl boronic acid occurs through ligand exchange, followed by C–Pd bond insertion across the alkene. This forms an organic metallic intermediate, which undergoes β-hydride elimination to yield the desired product coordinated to the nanoparticle. The catalyst is regenerated through oxidation of the metal-hydride in the presence of molecular oxygen and acetic acid, while the functionalized amine is exchanged for unfunctionalized substrate. Further investigations are needed to confirm and refine this proposed mechanism.

The developed method not only demonstrates compatibility with 1°, 2°, and 3° amines but also showcases its ability to facilitate chain walking reactions. Moreover, it provides practical and scalable solutions to address longstanding challenges in drug synthesis. The implications of this research extend far beyond the laboratory, as it opens up new possibilities for pharmaceutical development. By harnessing the power of the Mizoroki–Heck reaction with aryl boronic acids, researchers can now expedite the synthesis of 3,3-diarylallylamines, ultimately accelerating the discovery and development of novel drugs targeting G protein-coupled receptors. This breakthrough has the potential to revolutionize the pharmaceutical industry, improving drug accessibility and affordability for patients worldwide. Its impact on drug synthesis and the potential for transforming the pharmaceutical landscape cannot be overstated. This innovative approach sets the stage for further advancements in the field and offers hope for the discovery of new and more effective medications.

Prof. Michael Christopher Young

Michael Young was born in King, N.C. (approximately where Mayberry of Andy Griffith fame would be if it were real). He always knew he wanted to be a scientist, and while studying at Western Carolina University decided that chemistry was a better career choice than trying to genetically engineer Pokémon. He began his independent career after a PhD (2014) at UC – Riverside with Prof. Richard Hooley and a postdoc (2014 – 2016) at UT – Austin with Prof. Guangbin Dong. His group is interested in developing more sustainable routes to biologically relevant compounds, with a particular interest in G-protein coupled receptor-agonists and antagonists.

Olutayo Nathanael Farinde

Olutayo Nathanael Farinde is a PhD student currently working in the Young lab at The University of Toledo. He holds a BS degree in Analytical and Environmental Chemistry from the University of Ibadan, Nigeria, which he completed in 2019. At The University of Toledo, Nate’s research focuses on the area of C–H functionalization and alkene functionalization of amines. He is interested in developing novel synthetic methods which can be used to synthesize biologically-active molecules. When he’s not at the bench, Nate enjoys learning new computational methods.

 

Dr. Satheesh Vanaparthi

Satheesh Vanaparthi was born and raised in Telangana, India. He obtained his BSc and MSc from Osmania University and later received his PhD from Indian Institute of Technology – Guwahati, India (Prof. T. Punniyamurthy, 2019). After a postdoc at the Technion-Israel Institute of Technology, Israel (Prof. Graham de Ruiter), Satheesh moved to The University of Toledo, USA to work with the Young lab where he is currently working on rhodium and palladium-catalysed transformations.

Kendra Kumar Shrestha

Kendra hails from Nepal. He obtained his BSc and MSc from Tribhuvan University. In 2019, he moved to The University of Toledo to pursue his Ph.D. with Prof. Michael C. Young where he is working on palladium-catalysed selective functionalisations of aminees as wel as cycloaddition reactions exploiting organo-supramolecular catalysis.

Carmen Rose Rhinehalt

Carmen is a chemistry major with a passion for how and why the world works. She is currently working on the deuteration of benzoic acid derivatives and would like to transfer everything she has learned in the lab and chemistry to the development of cosmetic products. In her free time, Carmen likes to try new recipes and bake all kinds of sweets!

Dr. Vinod Gokulkrishna Landge

Vinod obtained his PhD from the National Chemical Laboratory in Pune, India, in 2019, where worked with Prof. Ekambaram Balaraman. He then joined the Young lab where he worked extensively on Pd and organocatalysis. He current works as a Process Development Scientists at Piramal Pharma Solutions.
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Emerging Investigator: Liang-An Chen at Nanjing Normal University, China

Emerging Investigator: Liang-An Chen

Position          Professor

Education       2011–2014  Xiamen University                            Ph.D.

                       2008–2011  Xiamen University                            M.Sc.

                       2004–2008  Fuyang Normal University                B.Sc.

ORCID            0000-0003-3423-3390

Read Liang-An Chen’s Emerging Investigator Series article in Organic Chemistry Frontiers and learn more about him.

     
  Redox-active alkyl xanthate esters enable practical C–S cross-coupling by nickel catalysis  

 

A new nickel catalysis strategy that harnesses readily accessible alkyl xanthate esters, while previously well-studied as alkyl radical precursors, herein as ideal sulfenylating agents via an unprecedented C–S bond activation pattern.

 

  From the themed collection: OCF Emerging Investigator Series  
  The article was first published on 11 Apr 2023  
  Org. Chem. Front., 2023, 10, 2505-2516  
  https://doi.org/10.1039/D3QO00136A  
     

My research interests

Key words: asymmetric catalysis, diene chemistry, alkene difunctionalization, oxidative cyclization, radical chemistry
My current research interests focus on methodology development, aiming to achieve transition metal-catalyzed asymmetric conjugated dienylation of propargyl alcohol derivatives (PADs) in a high regio-, chemo- and stereoselective manner and to explore their application in the development of new functionalization reactions based on the two conjugated C–C bonds. 

10 Facts about me

My favorite time of the day is the morning because I can enjoy reading the ASAP articles or the tweets on the public accounts.

What I look for first in a paper are insightful thoughts and challenges in the area.

If I were not an organic chemistry professor, I would be a historian or soldier.

In my spare time, I love playing games and sports with my two sons and traveling with my family.

The most difficult challenges I have faced were starting my independent research career and establishing an innovative and unique research program.

The first academic article I published in my independent research career is in Angewandte Chemie. This paper shaped the research interests of my group.

The most challenging work in my research is to achieve the asymmetric 1,3-dienylation of PADs with different carbon-based nucleophiles with high selectivity.

My advice for younger students is that hard work, persistence, strong will, and thinking more independently are key to success in their beginning research career.

An accomplishment I’m particularly proud of is that my students have become who they want to be after graduation.

The next goal of my research is to achieve structurally diverse conjugated dienes from PADs and to explore their further application in the synthesis of complex molecules with industrial needs.

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Emerging Investigator: Guangfan Zheng at Northeast Normal University, China

Emerging Investigator: Guangfan Zheng

Position          Associate Professor

Education       2014–2017  Northeast Normal University                Ph.D.

                       2012–2014  Northeast Normal University                M.Sc.

                       2006–2010  Jilin University                                      B.Sc.

ORCID            0000-0003-0201-6279

Read Guangfan Zheng’s Emerging Investigator Series article in Organic Chemistry Frontiers and learn more about him.

     
  Visible light-mediated NHC and photoredox co-catalyzed 1,2-sulfonylacylation of allenes via acyl and allyl radical cross-coupling  

 

Visible light-mediated NHC and photoredox co-catalyzed radical 1,2-sulfonylacylation of allenes via cross-coupling between an allyl radical and an NHC-stabilized acyl radical.

 

  From the themed collection: Frontiers Emerging Investigator Series  
  The article was first published on 03 Jan 2023  
  Org. Chem. Front., 2023, 10, 1047-1055  
  https://doi.org/10.1039/D2QO01993K  
     

My research interests

Key words: NHC catalysis, radical chemistry, cascade reaction, asymmetric catalysis, photocatalysis
My research interests focus on the development of N-heterocyclic carbene (NHC)-catalyzed, or visible light-mediated novel radical transformation, cascade reactions and asymmetric catalytic reactions. Particularly, we aim to develop efficient and highly selective catalytic transformation of aldehyde or carboxylic acid derivatives (such as carboxylic acid, ester, acyl fluoride, or amides) accessing value-added chemicals. 

10 Facts about me

When I was a kid, I wanted to be a scientist, as I enjoy new discoveries and challenges.

I published my first academic article in 2015 during my PhD studies in Nature Communications. This article demonstrates interesting and unpredictable N-centered radical addition to alkyne-initiated cascade transformations realizing animative muti-functionalization of alkynes.

The most challenging work about my research is to realize efficient asymmetric induction in NHC-catalyzed radical–radical cross-couplings.

In my spare time, I enjoy reading online novels.

My favorite science fiction novel is The Three-Body Problem.

The person who has had the greatest influence on my research career is my M.S. and Ph.D. supervisor Prof. Qian Zhang (Northeast Normal University). She was passionate about scientific research and was very inspiring.

The most important qualities of a role model are honesty, patience, and responsibility.

The most important thing I have learned is that opportunities are for those who are prepared.

I advise my students to keep enthusiasm and individual thinking about their research.

I lose track of time when discussing research progress and prospects with students.

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Emerging Investigator: Meng Li from Institute of Chemistry, Chinese Academy of Sciences (ICCAS)

Emerging Investigator: Meng Li

Position          Associate Professor

Education       2012–2015  Institute of Chemistry, CAS                Ph.D.

                       2009–2012  University of Chinese Academy of Sciences                                                                                                          M.Sc.

                       2005–2009  Shandong Normal University              B.Sc.

ORCID            0000-0003-4835-9293

Read Meng Li’s Emerging Investigator Series article in Organic Chemistry Frontiers and learn more about him.

     
  Advances in circularly polarized electroluminescence based on chiral TADF-active materials  

 

This review summarizes the development status of chiral TADF-active materials with CPEL, covering chiral perturbed TADF molecules, intrinsically chiral TADF molecules, and TADFsensitized fluorescent enantiomers.

 

  From the themed collection: Frontiers Emerging Investigator Series  
  The article was first published on 24 Sep 2022  
  Org. Chem. Front., 2022, 9, 6441-6452  
  https://doi.org/10.1039/D2QO01383E  
     

My research interests

Key words: organic synthesis, circularly polarized luminescence, organic light-emitting diodes
Meng Li’s research focuses on developing chiral optoelectronic materials for photoelectric conversion devices. He is also interested in understanding the structure–activity relationship between chiral molecules and their circularly polarized luminescence properties, as well as developing circularly polarized organic light-emitting diodes for display device of low power consumption. 

10 Facts about me

My favourite published academic article is the one on circularly polarized electroluminescence (CPEL) materials in Angew. Chem. Int. Ed. in 2018. In this work, we created a new system of CPEL materials based on chiral thermally activated delayed fluorescence (TADF) materials, providing an original research idea to solve the key problem of low device efficiency in the field of CPEL materials.

The academic group that helped me most is the Youth Innovation Promotion Association CAS. The members of this academic group are all outstanding young scientists under the age of 35 in CAS. They are active in various academic fields, and are ready to help others. Becoming a member of the group has greatly helped my scientific research.

The most important questions to be asked/answered in my research field include: (1) How to design and construct chiral luminescent materials with large asymmetry factor and high efficiency? (2) How to realize the transfer, amplification and regulation of chiral optoelectronic properties with multi-level chiral structures? (3) How to realize the creation of high-performance circularly polarized light emitting devices?

The most challenging work about my research is the application of chiral luminescent materials. I think this will require interdisciplinary collaborations between different academic fields, partnerships with industrial stakeholders, etc.

If I were not a scientist, I would be a secondary school teacher.

In my spare time, I enjoy reading biographical novels and playing Chinese chess.

One piece of career-related wisdom I would like to share with other early career scientists: be passionate about your research, and keep your curiosity.

The next big goal of my research is to improve the asymmetry factor of circularly polarized electroluminescence of chiral TADF-active materials.

My favourite book is Journey to the West.

My favourite time of the day is on the way to work in the morning. At that time, I am full of expectations for the whole day’s experiments.

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