A Simple Metal-Promoted Three-Step Access to n/5/m Angular Carbocyclic Systems
摘要:
A simple three-step access to n/5/m angular tricyclic skeleta from terminal cycloalkenylacetylenes, Cr(CO)(6), and propargylmalonate esters is described. The process involves a cyclopentannulation of propargylmaionates and enynyl Fischer carbenes, followed by a metal-promoted Copetype fragmentation of the propargyl unit The resulting 4-allenyl-carbonyl derivatives can undergo either a 5-exo annulation via a tin enolate or an unprecedented gold catalyzed 6-endo cyclization.