CARBON-CARBON BOND FORMATION VIA CARBONYL-CARBENE COMPLEXES.

Article abstract of DOI:10.1351/pac198355111689

The synthetic potential of carbonyl carbene complexes is demonstrated upon their reaction with alkynes. Both the elecrophilicity of the carbene carbon atom and the facile substitution of carbon monoxide are used for selective carbon-carbon bond formation. Nucleophilic alkynes (ynamines) add to the carbene carbon atom and then undergo insertion into the metal carbene bond. Chromium(0) is effective as a template in the annulation of carbene ligands bearing aromtic or vinylic side chains: Metal-assisted carbene transfer or both carbene and carbonyl transfer to alkynes are observed to yield indenes or 1,4-hydroquinones. The hydroquinone formation occurs regioselectively with respect to the alkyne incorporation and the annulation of diarylcarbene ligands. The synthetic utility of this reaction is exemplified by the synthesis of vitamins K and E.