Vinyllithium compds

Tri- -butylstannane added to a soln. of /-Pr2NLi in tetrahydrofuran at —60° to —80°, stirred for 20 min, solid CuCN added, warmed slowly to —60° to —50°, the resultant translucent green-yellow soln. treated dropwise with 2-methylcyclohex-l-enyl triflate, warmed to —25° to —20°, kept at the same temp, for 2 h, worked up, the crude oil (containing unwanted distannane) dissolved in ethyl acetate, treated with Ag-acetate, stirred in air for 2 h at room temp, (to oxidise the stannane) and worked up again product. Y 91%. This is part of a regiospecific route to vinyllithium compds. from ketones. F.e.s. S.R. Gilbertson et al.. Tetrahedron Letters 29, 4795-8 (1988). 

A soln. of startg. allyl alcohol in ether at 0" treated successively with 1.5 eqs. methyllithium, Me3SiSiMe3, and HMPA, ether removed under N2, and heated at 80 for 24 h - product. Y 75% (Z E 2 1). The allyloxides may also be generated in situ via carbophilic addition to a,P-ethyleneoxo compds. or by addition of vinyllithium to 0x0 compds. a further synthesis of 2-ethylenesilanes from 0x0 compds. is thus available. F.e.s. J.R. Hwu et al., J. Am. Chem. Soc. 110, 7252-4 (1988). 

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