Reaction of acyclic phosphine oxides with toluene-p-sulphonyl isocyanate and related reactions

Abstract

Acyclic phosphine oxides (1) form the corresponding imides (2) when treated with toluene-p-sulphonyl isocyanate (TsNCO) in aprotic solvents. Optically active phosphine oxides are racemised faster than imides are formed. The kinetics and mechanism of the racemisation process are discussed. The addition of TsNCO to methylphenyl-t-butylphosphine formed a 1 : 1 adduct, whereas addition to trimethyl phosphite gave dimethyl methylphosphonate together with trimethyl phosphate.