Cross-coupling Hiyama-type

Yoshida and co-workers have reported on the use of alkenyldimethyl(2-pyridil)silanes as versatile platforms for olefin synthesis.The combination of Mizoroki-Heck-type coupling and Hiyama cross-coupling provided a diverse range of stereodefmed polysubstituted olefins. 

Transmetallation of alkenylsilanes takes place with retention of the double bond configuration, as in other cross-coupling reactions [295]. Owing to the lower transmetallation rate, competing 1,2-insertion of the alkene in the intermediate organopalladium complex (as a Heck type reaction) may take place, which affects the regioselectivity of the Hiyama reaction in some cases (Scheme 1.38) [296]. This... 

Palladium catalysed Hiyama-type cross-coupling reactions of benzylic phosphates (74) with the aryl-silane (75) afforded corresponding di-arylmethanes (76) (Scheme 21). The reaction tolerated either electron-donating or electron-withdrawing functional groups providing products (76) in high to excellent yields. ... 

Tricyclic fused 3-aminopyridines 93 could also be assembled via intramolecular CpCo(C2H4)2-catalyzed [2- -2-1-2] cycloaddition between ynamides, nitriles, and alkynes (Scheme 1.26) [47]. Of particular interest, one of the cycloadducts could be used in a rare type of silylated pyridine Hiyama cross-coupling to give 95 in 77 % yield. 

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