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Enantioselective Cyanosilylation of Ketones with Amino Acid/BINAP/Ruthenium(II)‐Lithium Phenoxide Catalyst Systems
Author(s) -
Uemura Masato,
Kurono Nobuhito,
Sakai Yusuke,
Ohkuma Takeshi
Publication year - 2012
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201200027
Subject(s) - chemistry , binap , cyanohydrin , enantioselective synthesis , acetophenone , ruthenium , medicinal chemistry , catalysis , lithium (medication) , alkoxy group , organic chemistry , medicine , alkyl , endocrinology
Enantioselective reactions of simple ketones, α,α‐ and β,β‐dialkoxy ketones, and α‐alkoxy ketones with trimethylsilyl cyanide catalyzed by the bimetallic systems of amino acid/BINAP/ruthenium(II) complexes and lithium phenoxide have been studied [BINAP=2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl]. The Ru(PhGly) 2 (BINAP)‐lithium phenoxide system showed high enantioselectivity for the reaction of acetophenone derivatives to afford the cyanated products in up to 90% ee [PhGly=phenylglycinate]. For the cyanosilylation of dialkoxy ketones and α‐alkoxy ketones, the Ru( t ‐Leu) 2 (BINAP)‐lithium phenoxide system exhibited the best catalyst performance to produce the cyanohydrin derivatives in up to 99% ee and 98% ee , respectively [ t ‐Leu= tert ‐leucinate]. The excellent catalytic activity resulted in complete conversion in the reaction with a substrate‐to‐catalyst molar ratio (S/C) of 10,000 in the best cases.