Siloles Bearing Si-Vinyl and Si-Allyl Functions. 1,1-Organoboration and Protodeborylation

Abstract

1,1-Organoboration of dialkyn-1-yl(divinyl)silanes, dialkyn-1-yl(organo)(vinyl)silanes and dialkyn- 1-yl(allyl)(methyl)silane using triethylborane, BEt3, or 9-ethyl-9-borabicyclo[3.3.1]nonane, Et-9- BBN, afforded selectively silole derivatives with Si-vinyl and Si-allyl functions, respectively, bearing the dialkylboryl group in 3-position. The siloles are formed via intermolecular 1,1-alkylboration, followed by intramolecular 1,1-vinylboration. In the cases of several 3-diethylboryl-substituted siloles, smooth and essentially quantitative protodeborylation could be achieved by the reaction of the siloles with an excess of acetic acid at ambient temperature. All new siloles were characterized in solution by multinuclear magnetic resonance spectroscopy (1H, 13C, 11B and 29Si NMR).