Synthesis of Silylated Cyclobutanone and Cyclobutene Derivatives Involving 1,4-Addition of Zinc-Based Silicon Nucleophiles.

A copper-catalyzed conjugate silylation of various cyclobutenone derivatives with Me2 PhSiZnCl ⋅ 2LiCl or (Me2 PhSi)2 Zn ⋅ xLiCl (x≤4) to generate β-silylated cyclobutanones is reported. Trapping the intermediate enolate with ClP(O)(OPh)2 affords silylated enol phosphates that can be further engaged in Kumada cross-coupling reactions to yield silylated cyclobutene derivatives.