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Cofactor‐Free, Direct Photoactivation of Enoate Reductases for the Asymmetric Reduction of C=C Bonds
Author(s) -
Lee Sahng Ha,
Choi Da Som,
Pesic Milja,
Lee Yang Woo,
Paul Caroline E.,
Hollmann Frank,
Park Chan Beum
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201702461
Subject(s) - xanthene , nad+ kinase , chemistry , cofactor , moiety , photochemistry , electron transfer , enantioselective synthesis , stereochemistry , double bond , flavin group , nicotinamide , redox , medicinal chemistry , enzyme , catalysis , organic chemistry
Abstract Enoate reductases from the family of old yellow enzymes (OYEs) can catalyze stereoselective trans ‐hydrogenation of activated C=C bonds. Their application is limited by the necessity for a continuous supply of redox equivalents such as nicotinamide cofactors [NAD(P)H]. Visible light‐driven activation of OYEs through NAD(P)H‐free, direct transfer of photoexcited electrons from xanthene dyes to the prosthetic flavin moiety is reported. Spectroscopic and electrochemical analyses verified spontaneous association of rose bengal and its derivatives with OYEs. Illumination of a white light‐emitting‐diode triggered photoreduction of OYEs by xanthene dyes, which facilitated the enantioselective reduction of C=C bonds in the absence of NADH. The photoenzymatic conversion of 2‐methylcyclohexenone resulted in enantiopure ( ee >99 %) ( R )‐2‐methylcyclohexanone with conversion yields as high as 80–90 %. The turnover frequency was significantly affected by the substitution of halogen atoms in xanthene dyes.