Combined Directed <i>ortho</i> and Remote Metalation−Suzuki Cross-Coupling Strategies. Efficient Synthesis of Heteroaryl-Fused Benzopyranones from Biaryl <i>O</i>-Carbamates
作者:Clint A. James、Antonio Luiz Coelho、Matt Gevaert、Pat Forgione、Victor Snieckus
DOI:10.1021/jo900146d
日期:2009.6.5
LDA-induced migration of heterobiaryl O-carbamates 18, 21, 25, and 30 which, in turn, were prepared in good yield using a combined directed ortho lithiation (DoM)−transition-metal-catalyzed Suzuki cross-coupling strategy. An efficient and general route to a wide variety of heterocycles including coumestans 19a,c and the previously unknown isothiocoumestan ring system 22b has been thereby achieved.