Abstract Triethylborane (1) or trivinylborane (2) reacts with di (alkyn-1-yl) methylsilanes, MeSiH (C≡ CR) 2 3 [R= Bu (a), t-Bu (b), SiMe 3 (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 Me 2 Si (C≡ Ct-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 ...
