New Fischer carbene complexes of rhodium(i): preparation and 2-cyclopentenone ring synthesis by annelation to alkynes

J Am Chem Soc. 2004 Jan 21;126(2):470-1. doi: 10.1021/ja038817q.

Abstract

A new type of metal carbene complexes of group 9, specifically a cationic Fischer carbene of rhodium(I), has been synthesized from chromium carbene complexes via double transfer of carbene and CO ligands. These complexes reveal a different reactivity than other transition metal carbenes, including their chromium precursors, toward neutral and electron-poor alkynes, giving selectively polysubstituted cyclopentenones.