The propargyl phosphanes Ph2PCH2CCER3 (R3E = nBu3Sn, Ph3Sn, Me2PhSi, Pr3Si, nBu3Si) and (Me3Si)2PCH2CCSiPhMe2 are obtained in high yield; in contrast quenching PhCCCH2MgX with ClP(NEt2)2 preferentially affords (>70%) the novel phosphinoallene (Et2N)2PC(Ph)CCH2.