Enantioselective Cyanosilylation of Ketones Catalyzed by a Nitrogen-Containing Bifunctional Catalyst

✍ Scribed by Yan Xiong; Xiao Huang; Shaohua Gou; Jinglun Huang; Yuehong Wen; Xiaoming Feng

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 138 KB
• Volume: 348
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/adsc.200505418

✦ Synopsis

Abstract

An efficient and optically active, bifunctional tetraaza ligand (2__S__)‐N‐{(1__R__,2__R__)‐2‐[(S)‐pyrrolidine‐2‐carboxamido]‐1,2‐diphenylethyl}pyrrolidine‐2‐carboxamide has been developed for the addition of trimethylsilyl cyanide (TMSCN) to ketones. The bifunctional catalyst system based on a monometallic titanium complex was found to be a highly enantioselective catalyst to provide O‐TMS cyanohydrins with up to 94% ee. A possible transition state has been proposed to explain the origin of the activation and asymmetric inductivity.