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Double Asymmetric Hydrogenation of Linear β,β‐Disubstituted α,β‐Unsaturated Ketones into γ‐Substituted Secondary Alcohols using a Dual Catalytic System
Author(s) -
Arai Noriyoshi,
Satoh Hironori,
Komatsu Ryo,
Ohkuma Takeshi
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201701527
Subject(s) - allylic rearrangement , chemistry , catalysis , diamine , ligand (biochemistry) , organic chemistry , medicinal chemistry , receptor , biochemistry
Double asymmetric hydrogenation of linear β,β‐disubstituted α,β‐unsaturated ketones catalyzed by the DM‐SEGPHOS/DMAPEN/Ru II complex with t ‐C 4 H 9 OK afforded the γ‐substituted secondary alcohols in high diastereo‐ and enantioselectivities. Some mechanistic experiments suggested that two different reactive species, type (I) and (II), were reversibly formed in this catalytic system: Type (I) with the diamine ligand DMAPEN enantioselectively hydrogenated the enones into the chiral allylic alcohols, and type (II) without the diamine ligand diastereoselectively hydrogenated the allylic alcohols into the γ‐substituted secondary alcohols. This dual catalysis protocol was successfully applied to the reaction of a variety of aliphatic‐ and aromatic‐substituted enone substrates.