Several CSiMe3 and CGeMe3 protecteddialkynes have been synthesized and regioselectively deprotected by protodesilylation or protodegermylation. Catalytic amounts of CuBr in THF/MeOH or in aqueous acetone lead exclusively to protodegermylation. The Me3Si group was removed with KF/[18]-crown-6 in aqueous THF without affecting the GeMe3 group. CSiMe3 protected propargyl ethers are also selectively
benzostannoles 2 b and 2 c in 56% and 72% isolated yields, respectively. The effect of the silyl moiety at the sp-carbon atom of substrate 1 was also investigated. Both the Me2PhSi and MePh2Si groups were tolerated, and stannoles 2 d and 2 e were obtained in 83% and 87% yields. As shown in Figure 1, various benzostannoles 2 f–2 m were obtained in 71–84% yields. The structure of 2m was confirmed by