Reductions of Phosphine Oxides and Sulfides by Perchlorosilanes: Evidence for the Involvement of Donor-Stabilized Dichlorosilylene

Abstract

Hexachlorodisilane reduces phosphine oxides and sulfides to the corresponding phosphines with opposite stereoselectivities. Through quantum mechanical calculations, a new mechanistic picture is reported that explains these stereoselectivities. Phosphine oxides are shown to react via conventional phosphorane intermediates, but phosphine sulfides follow a dramatically different mechanism involving donor-stabilized SiCl₂