Ring Opening of Cyclic Vinylogous Acyl Triflates Using Stabilized Carbanion Nucleophiles: Claisen Condensation Linked to Carbon−Carbon Bond Cleavage
作者:David M. Jones、Marilda P. Lisboa、Shin Kamijo、Gregory B. Dudley
DOI:10.1021/jo100249g
日期:2010.5.21
Addition of stabilized carbanionic nucleophiles to cyclic vinylogous acyl triflates (VATs) triggers a ring-opening fragmentation to give acyclic β-keto ester and related products, much like those observed traditionally in the Claisen condensation. Unlike in the classical Claisen condensation, however, the VAT-Claisen reaction described herein is rendered irreversible by C−C bond cleavage, not by deprotonation
在环状乙烯基乙烯基三氟甲磺酸酯(VAT)中添加稳定的碳负离子亲核试剂会触发开环断裂,生成无环β-酮酯和相关产物,就像传统上在克莱森缩合反应中观察到的那样。但是,与经典的克莱森缩合不同,本文所述的VAT-克莱森反应通过C-C键裂解而不是通过活化的亚甲基产物的去质子化而变得不可逆。本文公开了该原始反应方法的全部细节,包括各种亲核试剂之间的细微差异如何影响对制备1,3-二酮,β-酮酸酯和β-酮膦酸酯的反应条件的正确选择。