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Titanium–salan‐catalyzed asymmetric sulfoxidations with H 2 O 2 : design of more versatile catalysts
Author(s) -
Talsi Evgenii P.,
Bryliakov Konstantin P.
Publication year - 2013
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.2968
Subject(s) - chemistry , catalysis , enantioselective synthesis , aryl , sulfide , electrophile , substituent , alkoxy group , titanium , alkyl , medicinal chemistry , combinatorial chemistry , organic chemistry
Titanium–salan complexes with 3,3’‐diphenyl substituents in the salicylidene rings of the salan ligand are efficient sulfoxidation catalysts, capable of catalyzing the asymmetric oxidation of bulky aryl benzyl sulfides with H 2 O 2 with good to high enantioselectivities . In this paper, substituent effects on titanium‐salan‐catalyzed enantioselective oxidation of sulfides to sulfoxides have been systematically investigated. Titanium–salan catalysts with halogen substituents at the 5,5’‐positions (3,3’‐H 2 dihydrogen substituted) have been found to catalyze the oxidation of both bulky aryl benzyl sulfides and small alkyl phenyl sulfides with good to high enantioselectivities . Kinetic data witness a direct attack of the sulfide to the electrophilic active oxygen species; a consistent reaction mechanism is proposed. Copyright © 2013 John Wiley & Sons, Ltd.