Synthesis and Reactivity of Acyclic (pentadienyl)iron(1+) Cations: Model Studies for the Preparation of the 8\u3cem\u3eE\u3c/em\u3e,10\u3cem\u3eZ\u3c/em\u3e,16\u3cem\u3eE\u3c/em\u3e,18\u3cem\u3eE\u3c/em\u3e-Tetraene Segment of Macrolactin A

Abstract

The dicarbonyl(1,2-dimethylpentadienyl)triphenylphosphineiron(1+) cation (11) has been prepared from methyl 4-methyl-2E,4E-hexadienoate in four steps. The cation (11) reacts with hydride and carbon nucleophiles in a regiospecific fashion to afford (3-methyl-2E,4Z-diene)iron complexes. Dicarbonyl(3-methyl-7-nitro-2E,4Z-heptadiene)triphenylphosphineiron (15), the product from the reaction of 11 with nitromethane anion, has been utilized as a precursor for nitrile oxide–olefin cyclocondensations