1578266-75-7Relevant academic research and scientific papers
Synthesis of 1-silacyclopent-2-ene derivatives using 1,2-hydroboration, 1,1-organoboration and protodeborylation
Khan, Ezzat,Tok, Oleg L.,Wrackmeyer, Bernd
, p. 280 - 285 (2014)
The reaction of di(alkyn-1-yl)vinylsilanes R1(H 2Ca?-CH)Si(C≡C - R)2 (R1 = Me (1), Ph (2); R = Bu (a), Ph (b), Me2HSi (c)) at 25°C with 1 equiv. of 9-borabicyclo[3.3.1]nonane (9-BBN) affords 1-silacyclopent-2-ene derivatives (3a, 3b, 3c, 4a, 4b), bearing one Si - C≡C - R function readily available for further transformations. These compounds are formed by consecutive 1,2-hydroboration followed by intramolecular 1,1-carboboration. Treated with a further equivalent of 9-BBN in benzene they are converted at relatively high temperature (80-100°C) into 1-alkenyl-1-silacyclopent-2-ene derivatives (5a, 5b 6a, 6b) as a result of 1,2-hydroboration of the Si - C≡C - R function. Protodeborylation of the 9-BBN-substituted 1-silacyclopent-2-ene derivatives 3, 4, 5, 6, using acetic acid in excess, proceeds smoothly to give the novel 1-silacyclopent-2-ene (7, 8, 9, 10). The solution-state structural assignment of all new compounds, i.e. di(alkyn-1-yl)vinylsilanes and 1-silacyclopent-2-ene derivatives, was carried out using multinuclear magnetic resonance techniques (1H, 13C, 11B, 29Si NMR). The gas phase structures of some examples were calculated and optimized by density functional theory methods (B3LYP/6-311+G/(d,p) level of theory), and 29Si NMR parameters were calculated (chemical shifts δ29Si and coupling constants nJ(29Si,13C)). Copyright
