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. (c) 2005 Elsevier Ltd. All rights reserved.