Organic & Biomolecular Chemistry Blog

The following Organic & Biomolecular Chemistry articles have all been recommened by the reviewers of the articles as being particularly interesting or particularly significant research. These have all been made free to access until 31st December 2014. The order they appear in the list holds no special meaning or ranking.

Catalytic asymmetric desymmetrization approaches to enantioenriched cyclopentanes
Madhu Sudan Manna and Santanu Mukherjee  
DOI: 10.1039/C4OB01649A, Perspective

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Corrin-based chemosensors for the ASSURED detection of endogenous cyanide
Felix Zelder and Lucas Tivana  
DOI: 10.1039/C4OB01889C, Perspective

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An efficient synthetic route to 1,3-bis(arylethynyl)isobenzofuran using alkoxybenzocyclobutenone as a reactive platform
Kenta Asahina, Suguru Matsuoka, Ryosuke Nakayama and Toshiyuki Hamura  
DOI: 10.1039/C4OB02012J, Communication

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Cationic azacryptands as selective three-way DNA junction binding agents
Jana Novotna, Aurelien Laguerre, Anton Granzhan, Marc Pirrotta, Marie-Paule Teulade-Fichou and David Monchaud  
DOI: 10.1039/C4OB01846J, Paper

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An efficient reagent for covalent introduction of alkynes into proteins
Jie Zhang, Dejun Ma, Dawei Du, Zhen Xi and Long Yi  
DOI: 10.1039/C4OB01873G, Communication

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Efficient merging of copper and photoredox catalysis for the asymmetric cross-dehydrogenative-coupling of alkynes and tetrahydroisoquinolines
Inna Perepichka, Soumen Kundu, Zoë Hearne and Chao-Jun Li  
DOI: 10.1039/C4OB02138J, Paper

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Naphthalene diimides as red fluorescent pH sensors for functional cell imaging
Filippo Doria, Marco Folini, Vincenzo Grande, Graziella Cimino-Reale, Nadia Zaffaroni and Mauro Freccero  
DOI: 10.1039/C4OB02054E, Paper

A recent communication in Organic and Biomolecular Chemistry reports the synthesis of a new reagent for the introduction of alkynes into proteins; a key step for click bioconjugation. The new diazonium reagent was prepared in a one-pot synthesis from commercially available 4-ethynylaniline.

Having optimized bioconjugation in a tyrosine containing small molecule, the new diazonium reagent was then used to covalently label proteins. Fluorescence labelling of protein surface tyrosine residues was achieved under mild conditions (pH 8.0) by reaction of the protein with the diazonium reagent and subsequent reaction with an azide-containing fluorescent compound. The new diazonium reagent was also used to achieve protein PEGylation; a strategy that could be employed to improve protein stability and reduce immunogenicity.

The new diazonium reagent can facilitate bioconjugation in a range of proteins and could be a useful addition to the biochemist’s toolbox.

Read the full article:
An efficient reagent for covalent introduction of alkynes into proteins
Jie Zhang, Dejun Ma, Dawei Du, Zhen Xi and Long Yi
Org. Biomol. Chem., 2014, DOI: 10.1039/C4OB01873G

The following Organic & Biomolecular Chemistry articles have all been recommened by the reviewers of the articles as being particularly interesting or particularly significant research. These have all been made free to access until 30th November. The order they appear in the list holds no special meaning or ranking.

Design strategies for bioorthogonal smart probes
Peyton Shieh and Carolyn R. Bertozzi
DOI: 10.1039/C4OB01632G, Review Article

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Stereoselective intermolecular [2 + 2]-photocycloaddition reactions of maleic anhydride: stereocontrolled and regiocontrolled access to 1,2,3-trifunctionalized cyclobutanes
Florian Hernvann, Gloria Rasore, Valérie Declerck and David J. Aitken
DOI: 10.1039/C4OB01383B, Paper

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Towards novel efficient and stable nuclear import signals: synthesis and properties of trimethylguanosine cap analogs modified within the 5′,5′-triphosphate bridge
Malgorzata Zytek, Joanna Kowalska, Maciej Lukaszewicz, Blazej A. Wojtczak, Joanna Zuberek, Aleksandra Ferenc-Mrozek, Edward Darzynkiewicz, Anna Niedzwiecka and Jacek Jemielity
DOI: 10.1039/C4OB01579G, Paper

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Catalytic asymmetric synthesis of the pentacyclic core of (−)-nakadomarin A via oxazolidine as an iminium cation equivalent
Nobuya Tsuji, Michael Stadler, Naoya Kazumi, Tsubasa Inokuma, Yusuke Kobayashi and Yoshiji Takemoto
DOI: 10.1039/C4OB01678E, Communication

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Short and efficient synthesis of fluorinated δ-lactams
Thomas J. Cogswell, Craig S. Donald, De-Liang Long and Rodolfo Marquez
DOI: 10.1039/C4OB01547A, Paper

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An efficient route to synthesize isatins by metal-free, iodine-catalyzed sequential C(sp3)–H oxidation and intramolecular C–N bond formation of 2′-aminoacetophenones
Venkatachalam Rajeshkumar, Selvaraj Chandrasekar and Govindasamy Sekar
DOI: 10.1039/C4OB01564A, Paper

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5-Nitroindole oligonucleotides with alkynyl side chains: universal base pairing, triple bond hydration and properties of pyrene “click” adducts
Sachin A. Ingale, Peter Leonard, Haozhe Yang and Frank Seela
DOI: 10.1039/C4OB01478B, Paper

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Cross-strand histidine–aromatic interactions enhance acyl-transfer rates in beta-hairpin peptide catalysts
M. Matsumoto, S. J. Lee, M. R. Gagné and M. L. Waters
DOI: 10.1039/C4OB01754D, Paper

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The asymmetric syntheses of pyrrolizidines, indolizidines and quinolizidines via two sequential tandem ring-closure/N-debenzylation processes
Stephen G. Davies, Ai M. Fletcher, Emma M. Foster, Ian T. T. Houlsby, Paul M. Roberts, Thomas M. Schofield and James E. Thomson
DOI: 10.1039/C4OB01737D, Paper

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Organocatalytic Michael addition–lactonisation of carboxylic acids using α,β-unsaturated trichloromethyl ketones as α,β-unsaturated ester equivalents
Louis C. Morrill, Daniel G. Stark, James E. Taylor, Siobhan R. Smith, James A. Squires, Agathe C. A. D’Hollander, Carmen Simal, Peter Shapland, Timothy J. C. O’Riordan and Andrew D. Smith
DOI: 10.1039/C4OB01788A, Paper

The Ugi reaction was one of the very first multicomponent reactions exploited to develop chemical libraries, which further extended to combinatorial, solid phase and flow synthesis for evolving new lead structures of active agents. Implementing the Ugi reaction in combination with other organic reactions enlarges the chemical diversity of possible products.

Researchers at Vrije University Brussel, led by Steven Ballet, have made a step forward by executing a one-pot Ugi-Huisgen tandem reaction and found an alternative high atom economy pathway for the synthesis of conformationally constrained, amino-triazoloazepinone-containing di- and tripeptides.

Strategically, they have used an unconventional azide containing acid, and alkyne amine along with traditional aldehydes and isocyanides. By using equimolar reactants with very mild reaction conditions, they were able to observe total conversion to the linear Ugi-compounds equipped with azide and alkyne functionality. Furthermore, they have cyclised the resulting compounds into the respective triazoles, by performing a catalyst-free Huisgen cycloaddition reaction in a sealed tube.

Variation in substitution patterns and tolerance of a large array of aldehydes in this methodology will open a new avenue for the synthesis of various building blocks to be used in peptidomimetics with a wide range of applications.

Find out more in their Communication:

Efficient synthesis of conformationally constrained, amino-triazoloazepinone-containing di- and tripeptides via a one-pot Ugi–Huisgen tandem reaction
T. M. A. Barlow, M. Jida, D. Tourwéa and S. Ballet
DOI: 10.1039/C4OB01381F