Synthetic application of Silylated Allylphosphonates

Abstract

The allylphosphonates and vinylphosphonates which had been synthesized through Arbuzov phosphorylation and Horner-Wadsworth-Emmons reaction of bisphosphonate with the aldehydes each, were silylated with trimethylsilylchlorides, to give α-, or γ- silylated products. The double bond of the silylated mixtures were isomerized to near side of the silyl group by excess base(LHMDS) used during the silylation. Fridel-Crafts reaction of the prepared α, γ-silylated mixtures afforded β, γ-unsaturated-δ-keto-phosphonates and α, β-unsaturated-δ-keto-phosphonates and then mixtures treated with an equivalent triethylamine afforded β, γ-unsaturated-δ-keto-phosphonates which are an useful precursor to synthesize a long polyethylenic chain. Introduction of trimethylsilane to allylphosphonates supplies several advantages to Horner-Wadsworth-Emmons olefination, in that it could to block γ-addition and proton abstraction of free allylphosphonates. Lithiated 3-trimethylsilylallylphosphonates treated with variously aldehydes, afforded dienylsilanes and 1-substituted-3-trimethyl silylallylphosphonates, also afforded 3-substituted dienylsilane in a good yield.