Synthesis of the First Triphosphabutadiene

Abstract

A new example for the replacement of carbon by phosphorus is provided by the red triphosphabutadiene 2. It has been prepared via two different routes: from the phosphapentadiene 1 by reaction with bases B and by condensation of a 1,3-diphosphapropene with a phosphane. In the crystal, 2 has cisoid double bonds (Aryl = 2,4,6-tri-tert-butylphenyl).