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Indexed by:期刊论文

Date of Publication:2011-11-01

Journal:CHINESE CHEMICAL LETTERS

Included Journals:Scopus、SCIE、ISTIC、CSCD

Volume:22

Issue:11

Page Number:1285-1288

ISSN No.:1001-8417

Key Words:Cyanohydrin; Bifunctional catalyst; Salen; TMSCN; Diphenylphosphine oxide

Abstract:A novel enantiopure salen ligand bearing a diphenylphosphine oxide on the 3-position of one aromatic ring was synthesized and combined with Ti(Oi-Pr)(4) as a monometallic bifunctional catalyst for asymmetric cyanosilylation reaction of aldehydes with trimethylsilyl cyanide (TMSCN). The catalyst system exhibited excellent activity and moderate enantioselectivity. The addition of TMSCN to 4-nitrobenzaldehyde in the presence of 1 mol% catalyst loading could complete within 10 min at ambient temperature. An intramolecularly cooperative catalysis was observed in this system wherein the central metal Ti(IV) is suggested to play a role of Lewis acid to activate aldehydes while the appended diphenylphosphine oxide worked as Lewis base to activate TMSCN. (C) 2011 Xiao Bing Lu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.