Polymeric salen-Ti(IV) or V(V) complex catalyzed asymmetric synthesis of O-acetylcyanohydrins from KCN, Ac₂O and aldehydes

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• 作者：Huang ; Wei ; Song ; Yuming ; Wang ; Jing ; Cao ; Guoying ; Zheng ; Zhuo
• 关键词：O-Acetyl cyanohydrins ; Recyclable polymeric salen-Ti(IV) complexes ; Polymeric salen-V(V) complexes ; Potassium cyanide ; Aldehyde ; Asymmetric cyanation
• 刊名：Tetrahedron
• 出版年：2004
• 期刊代码：107_00404020
• 类别：ch
• 出版时间：November 8, 2004
• 卷：60
• 期：46
• 页码：10469-10477
• 文件大小：387 K

摘要

Polymeric salen-Ti(IV) and V(V) complexes were employed in the enantioselective O-acetyl cyanation of aldehydes with potassium cyanide and acetic anhydride. The crosslinked polymeric salen-Ti(IV) catalyst exhibited good activities and enantioselectivities, up to 91%ee with 99%conversion was obtained at −20°C with 1mol%of catalyst (based on bimetallic catalytic unit). Moreover, six consecutive recyclings with the easily recovered crosslinked polymeric catalyst showed no obvious decrease in either activity or enantioselectivity. Linear polymeric salen-V(V) catalyst showed good catalytic efficiency too, up to 94%ee with 99%conversion was obtained at −42°C with 5mol%of catalyst.