Studies of the reaction of trivalent phosphorus compounds with dialkyl acetylenedicarboxylates in the presence of carbon dioxide

Abstract

Alkyl diphenylphosphinites react with dialkyl acetylenedicarboxylates in the presence of carbon dioxide to form 1,2-oxaphosphol-3-enes (5) which in the presence of excess phosphinite decompose to give di-ylides (6). The 1,2-oxaphosphol-3-enes (5) from dialkyl phenylphosphonites and trialkyl phosphites react with a further phosphorus component to give the ylides (9) which can readily be converted into dialkyl 1,2,2-tris(alkoxycarbonyl)ethylphosphonates (11). Studies using ¹³C- and ²H-labelled precursor provide evidence for rearrangement occurring via ketene intermediates.