Reactivity of alkynylsilanes towards B-halogeno-1,3,2-diselenaborolanes with an annelated dicarba-closo-dodecaborane(12) unit

Abstract

Abstract The C≡C bond of alkynylsilanes undergoes 1,2-haloboration with 2-halogeno-1,3,2-diselenaborolano-4,5-[1,2-dicarba-closo-dodecaborane(12)], in competition with reversible insertion into one of the B–Se bonds (selenoboration) to afford a seven-membered ring and finally, by elimination of Me3Si–X (X = Cl, Br, I), the corresponding B-alkynyl derivatives. The reactions were monitored by NMR spectroscopy (11B, 13C, 29Si and 77Se NMR). The proposed solution-state structures are also supported by DFT calculations of single molecule geometries and NMR parameters [B3LYP/6-311 + G(d,p) level of theory].