Copper(I) tert-butoxide-promoted 1,4 Csp2-to-O silyl migration:: Generation of vinyl copper equivalents and their stereospecific cross-coupling with allylic, aryl, and vinylic halides

Successive treatment of the (Z)-gamma-trimethylsilyl allylic alcohols with copper(I) tert-butoxide and allylic halides followed by the tetrabutylammonium fluoride-assisted hydrolysis produced the allylation products, 2,5-alkadien-1-ols, with complete retention of configuration. Similar treatment of the organometallic intermediates with aryl and vinylic halides in the presence of palladium(0) catalyst gave the corresponding cross-coupling products in good yields. The stereoselective preparation of the starting materials is also described.