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A simple metal-promoted three-step access to n/5/m angular carbocyclic systems.

Organic letters (2013-01-12)
José Barluenga, Ana Álvarez-Fernández, Tatiana Suárez-Rodríguez, Ángel L Suárez-Sobrino, Miguel Tomás
ABSTRACT

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.

MATERIALS
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Product Description

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