Premium
Effective Activation of the Chiral Salen/Ti(O i Pr) 4 Catalyst with Achiral Phenolic N ‐Oxides as Additives in the Enantioselective Cyanosilylation of Ketones
Author(s) -
He Bin,
Chen FuXue,
Li Yan,
Feng Xiaoming,
Zhang Guolin
Publication year - 2004
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200400411
Subject(s) - chemistry , cyanohydrin , enantioselective synthesis , catalysis , reactivity (psychology) , asymmetric induction , organic chemistry , trimethylsilyl , propylene oxide , titanium , ketone , trimethylsilyl cyanide , medicinal chemistry , polymer chemistry , ethylene oxide , polymer , medicine , alternative medicine , pathology , copolymer
The activation of chiral titanium( IV ) complexes with phenolic N ‐oxides additives has been found to provide an alternative strategy for the asymmetric cyanosilylation of ketones. By using 10 mol % of chiral salen−titanium( IV ) complex in combination with 1 mol % achiral phenolic N ‐oxide as an additive, aromatic, aliphatic and heterocyclic ketones have been converted into the corresponding cyanohydrin trimethylsilyl ethers in 58−96% yields with 56−82% ee . Several factors concerning the reactivity and enantioselectivity have been discussed. A catalytic cycle based on experimental phenomena and studies has been proposed to explain the origin of this activation and the asymmetric induction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)