Synthesis and oxidation of the decarbonylated adducts generated from alkenes and tricarbonyl(vinylketene)iron(0) complexes

Abstract

The tricarbonyl(vinylketene)iron(0) complex 6 reacted with dimethyl maleate, dimethyl fumarate, (E)-methyl 4-oxopent-2-enoate and (E)-ethyl 4,4,4-trifluorobut-2-enoate to give decarbonylated adducts 7–10 respectively. An X-ray crystal structure analysis of the adduct 7, formed from the complex 6 and dimethyl maleate, and a mechanistic explanation for the formation of the adducts are presented. Oxidation of the adducts 7–10 using (NH₄)₂Ce(NO₃)₆ gave a range of organic products including the tetrasubstituted cyclopropanes 20 and 23–25, the cyclobutane-1,2-dione 22, the trisubstituted lactone 21 and the α,β-unsaturated ketone 26.