Reaction of Bis(alkynyl)silanes with Tris(pentafluorophenyl)borane: Synthesis of Bulky Silole Derivatives by Means of 1,1-Carboboration under Mild Reaction Conditions
Abstractmagnified imageThe strong Lewis acid tris(pentafluorophenyl)borane [B(C6F5)3] reacts rapidly with dimethylbis(phenylethynyl)silane (1c) at room temperature in toluene by shift of a pentafluorophenyl (C6F5) group and formation of a new carbon‐bis(pentafluorophenyl)boron linkage [CB(C6F5)2] in a sequence of 1,1‐carboboration reactions to yield the 4‐bis(pentafluorophenyl)boryl/3‐pentafluorophenyl‐substituted 1,1‐dimethyl‐2,5‐diphenylsilole derivative 7c. The analogous reaction of bis(trimethylsilylethynyl)diphenylsilane (1d) with tris(pentafluorophenyl)borane gave the corresponding boryl‐substituted silole derivative (7d) featuring six bulky substituents attached at the central heterocyclic framework. Both the starting materials (1c, 1d) and the products (7c, 7d) were characterized by X‐ray crystal structure analyses.
1,1-Carboboration
作者:Gerald Kehr、Gerhard Erker
DOI:10.1039/c1cc15628d
日期:——
The use of very electrophilic boranes RB(C(6)F(5))(2) widens the scope of the 1,1-carboboration reaction substantially. Simple terminal alkynes HC identical withCR undergo this reaction with the RB(C(6)F(5))(2) reagents rapidly under mild conditions to give high yields of very useful new alkenylborane products. Even internal alkynes RC identical withCR undergo 1,1-carboboration with the RB(C(6)F(5))(2)