ol303269r_si_001.cif (32.23 kB)

A Simple Metal-Promoted Three-Step Access to n/5/m Angular Carbocyclic Systems

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posted on 01.02.2013 by José Barluenga, Ana Álvarez-Fernández, Tatiana Suárez-Rodríguez, Ángel L. Suárez-Sobrino, Miguel Tomás
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 propargylmalonates and enynyl Fischer carbenes, followed by a metal-promoted Cope-type 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.