Synthèse et étude chimique préliminaire des pentadiényl-2,4-phosphines

Abstract

A penta-2,4-dienylphosphine oxide is easily obtained by reaction of methylmagnesium iodide with 1-oxa-2-phosphacyclo-hepta-4,6-diene followed by two more intermediate steps. The corresponding phosphine may be obtained either by trichlorosilane reduction of the oxide or nickelocene reduction–complexation of the sulfide. It seems that the dienic part of penta-2,4-dienylphosphines cannot be involved in a η4-complexation for steric reasons. The oxides are valuable precursors for conjugated trienes through Wittig–Horner reactions with carbonyl compounds.