Synthesis, structure, and stability of a set of C-stereogenic heteroditopic P, S ligands

Abstract

This study focuses on synthesis and investigation of coordination modes of phosphorus and sulfur-containing C-stereogenic compounds, prepared from thioanisole. Isolation of the C-stereogenic organolithium compound [RR'CHLi·2THF]2 (R = C6H5S, R’ = (CH3)3Si, THF = tetrahydrofuran) instead of in situ usage turned out to be mandatory for controlled reactivity. Variation of the steric and electronic properties of the substituents at phosphorus furnished three different phosphane substituted P, S ligands RR'CHPPh2, RR'CHP(N(C2H5)2)2, and RR'CHP(t-C4H9)2. Furthermore, the corresponding chalcogenphosphoranes were synthesized by oxidation with elemental sulfur and selenium. Preliminary investigation of the coordination behavior of RR'CHP(t-C4H9)2, RR'CHP(S)(t-C4H9)2 and RR'CHP(Se)(t-C4H9)2 towards coinage metals was explored with Au(tht)Cl, both for the phosphanes and the corresponding phosphoranes. Intermolecular aurophilic interactions have been observed for the selenophosphorane exclusively.