siloles is described. The reaction of 1-hydrosilyl-4-silyl-1,3-enynes with diisobutylaluminumhydride (DIBAL-H) gave multisubstituted siloles in good to high yields. This method could be applied to the synthesis of benzosiloles using 2-hydrosilyl-1-(silylethynyl)benzenes as substrates. The silole formation was also promoted even by a substoichiometric amount of DIBAL-H. The reaction provides a straightforward
Using inexpensive and safe EtOCS2K as a thiol surrogate and tetrabutylphosphonium bromide and H2O as a mixed solvent, the reaction provided a range of substituted thiophenes in moderate to good yields. In addition, 2,3,4,5-tetrasubstituted thiophenes were able to be prepared under mild reaction conditions by electrophilic heterocyclization with NH4I and EtOCS2K in good yields.
Intramolecular alkyne germylzincation giving access to a wide range of germoles is achieved from triarylhydrogermanes in the presence of diethylzinc and AIBN as radical initiator.
We developed a synthetic route to unsymmetrically polysubstituted germoles bearing different substituents from 1-hydrogermyl-4-silyl-1,3-enynes. The reaction proceeded with 0.5 equiv of diisobutylaluminumhydride. Various 2-silylgermoles including benzogermoles were obtained in good to excellent yields. 2-Germylbenzogermoles could be also successfully synthesized from 1-hydrogermyl-4-germyl-1,3-enynes
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