Vinylmetal compounds

Boron (13) and aluminum hydrides (104) add cis to acetylenes, forming substituted vinylmetal compounds. Hydrolysis of these compounds provides a route to cis-olefins. 

N-halogenodicarboxylic acid imides 18, 367 Vinylmetal compounds (s. a. Vinyl derivatives)... 

The key step of the synthesis of racemic methanophenazine (rac-10) implies the coupling of the saturated Q component rac-29 to the unsaturated C19 component 39, which is needed for the generation of the terpenoid side chain. To begin with, the sp -sp cross-coupling between alkylmetal compounds released from rac-29 in situ and vinylmetal derivatives from 39 posed consid-... 

Yamamoto et al. have systematically studied the Lewis acid-catalyzed carbosilylation of alkynes with allylsilanes and related compounds [512]. They have disclosed that the EtAlCl2 (cat.J-MeaSiCl (excess) catalyst system or a sub-stoichiometric amount of HfC effectively induces the trans-aUylsilylation of the alkynes (Scheme 10.192) [514]. The HfCLj-promoted method, in particular, is quite useful for stereo- and regioselective aUylsilylation of a variety of aUylsilanes under mild conditions. In sharp contrast to the mechanism proposed by Jung et al., Yamamoto et al. have proposed that EtAlCh or HfCLi adds to an alkyne, the activated alkyne is allylated by an allylsilane, and the resulting vinylmetal becomes an aUylsilylation product by transmetalation. 

In addition, numerous reagents and methods have also been investigated for the preparation of these compounds. The stereoselective preparations of metal enolates. vinylmetals, and allylmetals of silicon and tin are of special interest because they are employed as useful reagents in organic synthesis. 

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