Copper(I) <i>tert</i>-Butoxide-Promoted 1,4 C<sup>sp</sup><sup><sup>2</sup></sup>-to-O Silyl Migration: Generation of Vinyl Copper Equivalents and Their Stereospecific Cross-Coupling with Allylic, Aryl, and Vinylic Halides
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 vinylichalides in the presence of palladium(0) catalyst gave the corresponding cross-coupling products in good yields. The stereoselective