October 2017 – Organic & Biomolecular Chemistry Blog

Archive for October, 2017

Unexpected divergent reactivity in Pt-catalyzed cyclizations of 1,5-bisallenes

19 Oct 2017

As a result of their unique physical and chemical properties, allenes have become key building blocks in modern organic synthesis. The discovery and development of their varied reactivity have been extensively reported on in recent years, however, application to more challenging bisallene systems has been comparatively limited.

In her group’s recent OBC publication, Prof. María Paz Muñoz of the University of East Anglia sought to fill this gap in the bisallene literature. The study discusses the development of an unprecedented Pt-catalyzed cyclization of 1,5-bisallenes in the presence of oxygen nucleophiles to selectively access 6- and 7-membered rings.

After initial screening, it was observed that selectivity was highly sensitive to the reaction conditions and could, therefore, be tuned to yield the desired molecular scaffold. Interestingly, in the presence of nucleophilic alcohols, vinyltetrahydropyridines are formed preferentially while the formation of di- and tetrahydroazepines are favoured when water is used.

Exhaustive mechanistic studies provided insight into this divergent reactivity. It was determined that different mechanisms operate depending on the nucleophile and electronic nature of the bisallene (as a result of its nitrogen tether). It is proposed that, in the presence of nucleophilic alcohols, 6-membered vinyltetrahydropyridines are preferentially formed as a result of a platinum hydride active catalyst—which are known to form from platinum complexes and alcohols. Tetrahydroazepines, on the other hand, are favoured when water is used as the nucleophile, proceeding first through a nucleophilic attack followed by carbocylization to form the 7-membered ring.

Understanding this complex mechanistic behaviour provides important insight into bisallene reactivity and will no doubt enhance the scope of this work’s application in organic and medicinal chemistry.

This communication is part of the OBC themed collection, Mechanistic Aspects of Organic Synthesis. You can read the rest of the collection here.

To find out more see:

Nucleophile dependent formation of 6- and 7-membered N-heterocycles by platinum-catalysed cyclisation of 1,5-bisallenes
María Teresa Quirós,César Hurtado-Rodrigo and María Paz Muñoz
DOI:10.1039/C7OB01469D

Victoria Corless is currently completing her Ph.D. in organic chemistry with Prof. Andrei Yudin at the University of Toronto. Her research is centred on the synthesis of kinetically amphoteric building blocks which offer a versatile platform for the development of chemoselective transformations with particular emphasis on creating novel biologically active molecules.

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What are your colleagues reading in Organic & Biomolecular Chemistry?

12 Oct 2017

The articles below are some of the most read Organic & Biomolecular Chemistry articles in April, May and June 2017.

Review Articles:

Design and synthesis of analogues of natural products
Martin E. Maier
DOI: 10.1039/C5OB00169B

Transition-metal catalyzed valorization of lignin: the key to a sustainable carbon-neutral future
Markus D. Kärkäs, Bryan S. Matsuura, Timothy M. Monos, Gabriel Magallanes and Corey R. J. Stephenson
DOI: 10.1039/C5OB02212F

Selective chemical labeling of proteins
Xi Chen and Yao-Wen Wu
DOI: 10.1039/C6OB00126B

Site-selective incorporation and ligation of protein aldehydes
Richard J. Spears and Martin A. Fascione
DOI: 10.1039/C6OB00778C

1,3-Dipolar cycloadditions of azomethine imines
Carmen Nájera, José M. Sansano and Miguel Yus
DOI: 10.1039/C5OB01086A

Organocatalytic synthesis of axially chiral atropisomers
P. Renzi
DOI: 10.1039/C7OB00908A

The application of design of experiments (DoE) reaction optimisation and solvent selection in the development of new synthetic chemistry
Paul M. Murray, Fiona Bellany, Laure Benhamou, Dejan-Krešimir Bučar, Alethea B. Tabor and Tom D. Sheppard
DOI: 10.1039/C5OB01892G

Recent advances in the synthesis and application of fluorescent α-amino acids
Alexander H. Harkiss and Andrew Sutherland
DOI: 10.1039/C6OB01715K

Communications & Papers:

Amidation of unactivated ester derivatives mediated by trifluoroethanol
Christopher G. McPherson, Nicola Caldwell, Craig Jamieson, Iain Simpson and Allan J. B. Watson
DOI: 10.1039/C7OB00593H, Communication

A rapid and efficient one-pot method for the reduction of N-protected α-amino acids to chiral α-amino aldehydes using CDI/DIBAL-H
Jakov Ivkovic, Christian Lembacher-Fadum and Rolf Breinbauer D
OI: 10.1039/C5OB01838B, Communication

A protocol for amide bond formation with electron deficient amines and sterically hindered substrates
Maria E. Due-Hansen, Sunil K. Pandey, Elisabeth Christiansen, Rikke Andersen, Steffen V. F. Hansen and Trond Ulven
DOI: 10.1039/C5OB02129D, Communication

A NHC-catalyzed 1,3-dipolar cycloaddition reaction of allyl ketones with azides: direct access to 1,4,5-trisubstituted 1,2,3-triazoles
Huijun Yuan, Lili Zhang, Zhantao Liu, Yang Liu, Jian Wang and Wenjun Li
DOI: 10.1039/C7OB00906B, Communication

A novel off–on fluorescent probe for sensitive imaging of mitochondria-specific nitroreductase activity in living tumor cells
Bo Huang, Wen Chen, Yong-Qing Kuang, Wei Liu, Xian-Jun Liu, Li-Juan Tang and Jian-Hui Jiang
DOI: 10.1039/C7OB00781G, Communication

FeCl₃ catalysed 7-membered ring formation in a single pot: a new route to indole-fused oxepines/azepines and their cytotoxic activity
K. Shiva Kumar, Meesa Siddi Ramulu, Bandari Rajesham, N. Praveen Kumar, Vani Voora and Rama Krishna Kancha
DOI: 10.1039/C7OB00715A,Paper

Copper-catalyzed oxidative decarboxylative coupling of α-keto acids and sulfoximines
Chaleena Pimpasri, Ladawan Sumunnee and Sirilata Yotphan
DOI: 10.1039/C7OB00776K, Paper

Tf₂NH-catalyzed formal [3 + 2] cycloaddition of oxadiazolones with ynamides: a simple access to aminoimidazoles
Yingying Zhao, Yancheng Hu, Xincheng Li and Boshun Wan
DOI: 10.1039/C7OB00701A, Communication

Cyclic dipeptide based cell-penetrating peptidomimetics for effective DNA delivery
Chilakapati Madhu, Chandrashekhar Voshavar, K. Rajasekhar and Thimmaiah Govindaraju
DOI: 10.1039/C7OB00167C, Communication

Synthesis, properties, and crystal structures of π-extended double [6]helicenes: contorted multi-dimensional stacking lattice
Takao Fujikawa, Nobuhiko Mitoma, Atsushi Wakamiya, Akinori Saeki, Yasutomo Segawa and Kenichiro Itami
DOI: 10.1039/C7OB00987A, Paper

Urotensin-II peptidomimetic incorporating a non-reducible 1,5-triazole disulfide bond reveals a pseudo-irreversible covalent binding mechanism to the urotensin G-protein coupled receptor
Salvatore Pacifico, Aidan Kerckhoffs, Andrew J. Fallow, Rachel E. Foreman, Remo Guerrini, John McDonald, David G. Lambert and Andrew G. Jamieson
DOI: 10.1039/C7OB00959C, Paper

Enantioselective total synthesis of (+)-arborescidine C and related tetracyclic indole alkaloids using organocatalysis
Vishal M. Sheth, Bor-Cherng Hong and Gene-Hsiang Lee
DOI: 10.1039/C7OB00473G, Communication

Asymmetric synthesis of CF₃-containing tetrahydroquinoline via a thiourea-catalyzed cascade reaction
Yuanyuan Zhu, Boyu Li, Cui Wang, Zhenghao Dong, Xiaoling Zhong, Kairong Wang, Wenjin Yan and Rui Wang
DOI: 10.1039/C7OB01013C, Communication

Palladium-catalyzed Suzuki–Miyaura coupling of amides by carbon–nitrogen cleavage: general strategy for amide N–C bond activation
Guangrong Meng and Michal Szostak
DOI: 10.1039/C6OB00084C, Paper

Ru(II)-Catalyzed annulation of benzamidines and alkynes by C–H/N–H activation: a facile synthesis of 1-aminoisoquinolines
P. P. Kaishap, G. Duarah, D. Chetia and S. Gogoi
DOI: 10.1039/C7OB00389G, Paper

2,2,2-Trifluoroethanol as a solvent to control nucleophilic peptide arylation
Diana Gimenez, Anica Dose, Nicholas L. Robson, Graham Sandford, Steven L. Cobb and Christopher R. Coxon
DOI: 10.1039/C7OB00295E, Communication

Regioselective 6-endo–dig iodocyclization: an accessible approach for iodo-benzo[a]phenazines
Sonu Kumar, Mohammad Mujahid and Akhilesh K. Verma
DOI: 10.1039/C7OB00671C, Paper

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Poster prize winners at the 11th Symposium on Biorelevant Chemistry

12 Oct 2017

Congratulations to the poster prize winners at the Symposium on Biorelevant Chemistry!

Organic & Biomolecular Chemistry are please to present prizes to these winners:

Ryotaro Yamada (Nagoya University, Graduate School of Science, Department of Chemistry)
Title: Probing auxin signaling with synthetic auxin-engineered receptor pair

Kieko Senda (Nagoya University, Graduate School of Science, Department of Chemistry)
Title: Photostable fluorescent nanoparticles encapsulating a NIR phospha-rhodamine dye

Organised by the Chemical Society of Japan, the Symposium on Biorelevant Chemistry took place from the 7th – 9th September 2017.

The winners receiving their prizes from Philippa Hughes (Executive Editor, Royal Society of Chemistry)

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Organic & Biomolecular Chemistry Blog

Archive for October, 2017

Unexpected divergent reactivity in Pt-catalyzed cyclizations of 1,5-bisallenes

Poster prize winners at the 11th Symposium on Biorelevant Chemistry

Congratulations to the poster prize winners at the Symposium on Biorelevant Chemistry!

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