1,1-Vinylboration and 1,1-Ethylboration of Di(alkyn-1-yl)silanes: Synthesis of New Siloles

Abstract

Triethylborane (1) or trivinylborane (2) reacts with di(alkyn-1-yl)methylsilanes, MeSiH(C≡C-R)2 3 [R = Bu (a), t-Bu (b), SiMe3 (c)], to give the novel chiral 1-silacyclopenta-2,4-dienes (siloles) 4a-4c or 5a-5c, respectively, by twofold 1,1-organoboration. Similarly, di(alkyn-1-yl)dimethylsilane Me2Si(C≡C-t-Bu)2 3d reacts with 2 to give the silole 5d. These are the first applications of 2 in 1,1-organoboration reactions. All products are characterized by multinuclear magnetic resonance (1H, 11B, 13C, 29Si NMR).