An unusual synthesis of 2,3‐dihydrophosphindole 1‐oxides

Abstract

A very simple route to dimeric phosphole oxides is reported as is the pyrolytic decomposition of these phosphorus‐bridged dimers. Like similar dimeric phosphole sulfides, these phosphole oxide dimers readily eliminate the bridging phosphorus grouping upon strong heating but, unlike the analogous sulfides, hydrogen transfer to give a 2,3‐dihydrophosphindole 1‐oxide rather than hydrogen elimination to give the fully unsaturated phosphindole oxide occurs. This hydrogen transfer is shown to be non‐stereospecific and some mechanistic implications of this are briefly discussed. Copyright © 1979 Journal of Heterocyclic Chemistry