Generation and regioselective reactions of α,α-bis(silyl)-substituted allylcopper reagents—synthesis of 1,1-disilylalkenes

Construction of highly sterically hindered 1,1-disilylated terminal alkenes

One direct and efficient procedure for the synthesis of 1,1-disilylated terminal alkenes is demonstrated in this paper. To overcome and rationally utilize the steric hindrance of silyl units, the cationic ruthenium catalyst [CpRu(MeCN)3]+ was found to be effective for Markovnikov hydrosilylation of 1-silyl terminal alkynes with high yields and excellent regioselectivity. Dissimilarities between alkyl and alkoxy silyl units lead to versatile product derivatizations toward a variety of useful building blocks.

A New Selective Approach to 1,1-Bis(silyl)-2-arylethenes and 1,1-Bis(silyl)-1,3-butadienes via Sequential Silylative Coupling−Heck Coupling Reactions

A novel selective route to 1,1-bis(silyl)-1-alkenes has been developed. Sequential one-pot silylative coupling exo-cyclization of 1,2-bis(dimethylvinylsiloxy)ethane followed by the reaction with Grignard reagents leads to the desired 1,1-bis(silyl)ethenes, which are then efficiently coupled in the presence of silver nitrate and palladium acetate with aryl or alkenyl idodides to give the corresponding 1,1-bis(silyl)-2-arylethenes or 1,1,4-trisubstituted 1,3-butadienes with high yield.

A Facile Synthesis of 1,1-Bis(silyl)ethenes

Symmetrical 1,1-bis(silyl)ethenes have been easily prepared via ruthenium complex-catalyzed silylative coupling cyclization of 1,2-bis(dimethylvinylsiloxy)ethane to give 2,2,4,4-tetramethyl-3-methylene-1,5-dioxa-2,4-disilacycloheptane with excellent selectivity and good yield, followed by its reaction with Grignard reagents. The cyclic product can also be effectively transformed into cyclic carbosiloxane, 2,2,4,4,6,6,8,8-octamethyl-3,7-dimethylene-1,5-dioxa-2,4,6,8-tetrasilacyclooctane.