The cycloaddition reactions of 2-ethoxy-3-phenylvinylketene iron(0) with alkynes to yield catechol derivatives

Tricarbonyl(3-ethoxy-4-phenyl-1-oxa-1,2,4-pentatrienone) iron(0) reacts with a variety of electron deficient and electron rich alkynes to produce catechol monoethyl ethers in moderate to good yield. Steric hindrance of the alkyne often exerts a stronger influence than electronic factors in determining the product distribution. The reaction with several alkyl, silyl, and aryl alkynes produced alkyne trimers as the major products.