Synthesis of 3-stannyl and 3-silyl propargyl phosphanes and the formation of a phosphinoallene

The group 14 chloropropargyls R3ECCCH2Cl (R3E = Bu3Sn, Ph3Sn, Me2PhSi, iPr3Si, nPr3Si, nBu3Si), obtained by a modified literature procedure, react with LiPPh2 to afford the novel propargyl phosphanes Ph2PCH2CCER3 in high yield, as viscous oils; (Me3Si)2PCH2CCSiPhMe2 is similarly obtained from LiP(SiMe3)2. In contrast, the reaction of PhCCCH2MgCl with ClP(NEt2)2 fails to produce a comparable propargyl phosphane, but generates preferentially (>70%) the novel phosphinoallene (Et2N)2PC(Ph)=C=CH2, which is characterised spectroscopically, and through its reaction with HCl. The coordination chemistry of representative phosphanes is explored with respect to platinum and palladium for the first time.