Preparation of Isotopically Substituted Methylphosphines

Abstract

The small-scale preparations of isotopically substituted methylphosphine and dimethylphosphine are best achieved using the reactions between the appropriate methyl iodide and PH₃ or MePh₂ in a KOH/dimethylsulphoxide slurry, as first described by Jolly. The procedures must be individually modified to minimize or avoid proton or methyl exchange with the solvent. Trimethylphosphine with non-equivalent methyl groups is obtained by an extension of the same procedure, but for small quantities of Me₃P containing three identical methyl groups the reaction of PCl₃ with ZnMe₂ has certain advantages over a Grignard reaction.