Copper(I) tert-butoxide-promoted 1,4 C-sp2-to-O silyl migration: Stereospecific allylation of (Z)-gamma-trimethylsilyl allylic alcohols

[GRAPHICS] The cyclic silyl ethers, 2,2-dimethyl-1-oxa-2-slia-3-cyclopentenes, were pr oduced by the treatment of (2)-gamma -trimethylsilyl allylic alcohols with a catalytic or stoichiometric amount of lithium tort-butoxide. On the other hand, successive treatment of the alcohols with copper(l) tert-butoxide an d allylic halides followed by the tetrabutylammmonium fluoride assisted hyd rolysis produced the allylation products, 2,5-alkadien-1-ols, with complete retention of configuration of the double bond.