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Stereocontrolled Synthesis of 1,4‐Dicarbonyl Compounds by Photochemical Organocatalytic Acyl Radical Addition to Enals
Author(s) -
Goti Giulio,
Bieszczad Bartosz,
VegaPeñaloza Alberto,
Melchiorre Paolo
Publication year - 2019
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.201810798
Subject(s) - chemistry , iminium , acylation , enantioselective synthesis , catalysis , radical , reactivity (psychology) , stereoselectivity , organocatalysis , conjugate , combinatorial chemistry , photochemistry , organic chemistry , medicine , alternative medicine , pathology , mathematical analysis , mathematics
We report a visible‐light‐mediated organocatalytic strategy for the enantioselective acyl radical conjugate addition to enals, leading to valuable 1,4‐dicarbonyl compounds. The process capitalizes upon the excited‐state reactivity of 4‐acyl‐1,4‐dihydropyridines that, upon visible‐light absorption, can trigger the generation of acyl radicals. By means of a chiral amine catalyst, iminium ion activation of enals ensures a stereoselective radical trap. We also demonstrate how the combination of this acylation process with a second catalyst‐controlled bond‐forming event allows to selectively access the full matrix of all possible stereoisomers of the resulting 2,3‐substituted 1,4‐dicarbonyl products.