2-YIidvl-1,3,2-oxathiaphosphole und -oxaselenaphosphole / 2-Ylidyl-1,3,2-oxathiaphospholes and -oxaselenaphospholes

Abstract

Ylidyl thioxophosphines or selenoxophosphines and phenacyl halides undergo addition in a 1:1 ratio and yield in the presence of triethylamine the title compounds. The molecular structure of an ylidyl oxathiaphosphole demonstrates a strong interaction between the ylid substituent and the heterocycle, making the exocyclic PC-bond unusually short and the endocyclic PO- and PS-bonds considerably longer than normal for a pyramidal phosphorus atom. The ylidyl chalcogenoxophosphines are oxidized by sulfur or selenium at the phosphorus atom and protonated at the ylidic carbon atom. No Wittig-type reaction is observed.