Synthesis of free and ligated 1,2-thiaphosphetanes – expanding the pool of strained P-ligands

Abstract

While P(V) 1,2-oxaphosphetanes were investigated in great detail over the past decades, the knowledge about P(V) 1,2-thiaphosphetanes is rather scarce, and P(III) derivatives are unknown. Herein, we present the synthesis of the first P(III) complex derivatives formed in the coordination sphere of group 6 metals and, additionally, the first unligated P(III) 1,2-thiaphosphetanes. The latter display an unusually low HOMO–LUMO gap thus constituting excellent candidates for redox-cycling organocatalysts.