Wikipedia
Dimethylphosphine
Dimethylphosphine is the organophosphorus compound with the formula (CH)PH, often written MePH. It is a malodorous gas that condenses to a colorless liquid just below room temperature. Although it can be produced by methylation of phosphine, a more practical synthesis involves the reduction of tetramethyldiphosphine disulfide with tributylphosphine:
[MeP(S)] + PBu + HO → MePH + SPBu + MeP(O)H