Organic & Biomolecular Chemistry Blog

In this HOT article Juan Dong and Da-Ming Du, Beijing Institute of Technology, present a new organocatalytic enantioselective Michael addition of 4-hydroxycoumarin to α,β-unsaturated ketones.

The article features a new kind of bifunctional primary amine–phophinamide catalyst, which when applied to catalyze the Michael reaction of 4-hydroxycoumarin to α,β-unsaturated ketones lead to the synthesis of the important pharmaceutical product Warfarin.

Highly enantioselective synthesis of Warfarin and its analogs catalysed by primary amine–phosphinamide bifunctional catalysts
Juan Dong and Da-Ming Du
DOI: 10.1039/C2OB26334C

In this Communication Peter O’Brien and colleagues from the University of York describe a short and efficient asymmetric synthesis of a chiral cyclohexenone derivative ((4S,5S)-dihydroxycyclohexen-1-one ). This derivative is a very useful synthon for a variety of natural products, as shown by O’Brien et al., who prepare 2 cyclohexenone natural products isolated from the mycelia of Lasiodiplodia theobromae.

The approach presented has been described as being ‘elegant chemistry which uses symmetry breaking reactions to quickly reach a synthetic goal.’

Find out more by downloading the Communication now….

Catalytic asymmetric synthesis of butane diacetal-protected (4S,5S)-dihydroxycyclohexen-1-one and use in natural product synthesis
David J. Burns, Shuji Hachisu, Peter O’Brien and Richard J. K. Taylor
DOI: 10.1039/C2OB26406D

In this HOT paper Antonio Arcadi, Università degli Studi di L’Aquila, and colleagues present a newly developed one-pot gold-catalysed approach to the assembly of 11H-indolo[3,2-c]quinolines from readily available unprotected 2-[2-(2-aminophenyl)ethynyl]anilines and aldehydes.

Arcadi et al. use the clever idea of first using a fast regio-selective intramolecular reaction, followed by a slower intermolecular condensation and subsequent cyclisation and final hydrogen transfer nicely provides a fast, synthetically efficient and elegant access to indolo[3,2-c]quinolines. With its broad scope, mild conditions and high regioselectivity this could be a valuable alternative to protocols previously described in the literature.

Find out more by downloading this paper today. It’s free to access for 4 weeks so grab it whilst you can.

An alternative one-pot gold-catalyzed approach to the assembly of 11H-indolo[3,2-c]quinolines
Giorgio Abbiati, Antonio Arcadi, Marco Chiarini, Fabio Marinelli, Emanuela Pietropaolo and Elisabetta Rossi
DOI: 10.1039/C2OB26380G

This manuscript from Zhong-Lin Lu and co-workers presents the preparation of a series of mononuclear and dinuclear zinc(II) complexes with ligands bearing different numbers of N-methyl groups, and includes a thorough kinetic study towards the hydrolytic cleavage of RNA and DNA model substrates.

The study focuses on the influence of steric effects on the catalytic efficiency and for the first time probes the effect of N-methylation of triazacyclododecane ligands. The N-methylation substantially reduces the co-operative behaviour between mononuclear zinc complexes and for the dinuclear complexes the activities are also substantially reduced but are still faster than the background reaction without the metal-complex.

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Steric effects on the catalytic activities of zinc(II) complexes containing [12]aneN₃ ligating units in the cleavage of the RNA and DNA model phosphates
Yang Song, Ju Zan, Hao Yan, Zhong-Lin Lu and Ruibing Wang
DOI: 10.1039/C2OB25624J