Issue 33, 2015

ω-Transaminases for the amination of functionalised cyclic ketones

Abstract

The potential of a number of enantiocomplementary ω-transaminases (ω-TAms) in the amination of cyclic ketones has been investigated. After a preliminary screening of several compounds with increasing complexity, different approaches to shift the equilibrium of the reaction to the amine products were studied, and reaction conditions (temperature and pH) optimised. Interestingly, 2-propylamine as an amine donor was tolerated by all five selected ω-TAms, and therefore used in further experiments. Due to the higher conversions observed and interest in chiral amines studies then focused on the amination of α-tetralone and 2-methylcyclohexanone. Both ketones were aminated to give the corresponding amine with at least one of the employed enzymes. Moreover, the amination of 2-methylcyclohexanone was investigated in more detail due to the different stereoselectivities observed with TAms used. The highest yields and stereoselectivities were obtained using the ω-TAm from Chromobacterium violaceum (CV-TAm), producing 2-methylcyclohexylamine with complete stereoselectivity at the (1S)-amine position and up to 24 : 1 selectivity for the cis : trans [(1S,2R) : (1S,2S)] isomer.

Graphical abstract: ω-Transaminases for the amination of functionalised cyclic ketones

Article information

Article type
Paper
Submitted
12 Jun 2015
Accepted
14 Jul 2015
First published
14 Jul 2015
This article is Open Access
Creative Commons BY license

Org. Biomol. Chem., 2015,13, 8843-8851

Author version available

ω-Transaminases for the amination of functionalised cyclic ketones

N. Richter, R. C. Simon, H. Lechner, W. Kroutil, J. M. Ward and H. C. Hailes, Org. Biomol. Chem., 2015, 13, 8843 DOI: 10.1039/C5OB01204J

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