The Synthesis of Phenols and Quinones via F ischer Carbene Complexes

Abstract Fischer carbene complexes can be broadly defined as those transition‐metal carbene complexes that have a low oxidation state, have an electrophilic carbene carbon , and usually have a heteroatom‐stabilizing substituent on the carbene carbon. Fischer complexes were the first examples of any type of transition metal carbene complexes to be reported. The reaction of Fischer carbene complexes with alkynes is facile, occurring just above ambient temperature, and resulting in the assembly of a benzene ring from the three carbons of the alpha, beta‐unsaturated carbine complex, the two carbons of the alkyne, and the carbon of a carbon monoxide ligand. The synthetic value of this reaction stems from its broad scope, the generally high yields for the process, and the fact that that the products can function as intermediates for the synthesis of a variety of aromatic compounds includingpara‐quinones. It is the most synthetically valuable of the large number of Fischer carbene complexes that have been developed for applications in synthetic organic chemistry. This chapter is the first comprehensive review that is limited to the synthesis of phenols and quinones from the reactions of Fischer carbene complexes with alkynes.