Reactions of Zirconocene鈥?-Aza-1,3-diene Complexes with Acyl Cyanides: Substrate-Dependent Synthesis of Acyl- or Non-Acyl-Substituted Pyrroles

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• 作者：Meijun Xiong ; Shasha Yu ; Xin Xie ; Shi Li ; Yuanhong Liu
• 刊名：Organometallics
• 出版年：2015
• 出版时间：December 14, 2015
• 年：2015
• 卷：34
• 期：23
• 页码：5597-5601
• 全文大小：377K
• ISSN：1520-6041

文摘

Insertion of acyl cyanides into azazirconacyclopentenes derived from 1,3-azadienes has been described, which affords acyl- or non-acyl-substituted pyrroles upon acidic quenching. These reactions are initialized through C鈺怬 insertion into the azazirconacycle to afford seven-membered oxaazazirconacycles. In the cases of 1,4- or 1,2,4-substituted azadienes, addition of a second molecule of acyl cyanide followed by cyclization upon acidic quenching leads to acyl-substituted pyrroles. In the cases of 1,3,4-substituted azadienes, the addition of a second molecule of acyl cyanide cannot proceed due to the steric hindrance caused by the R³ group on the zirconium intermediate. Acidic quenching of the resulting zirconium intermediate affords non-acyl-substituted pyrroles.