HYDROXY-SUBSTITUTED AND CARBOXY-SUBSTITUTED ALLYLSILANES - A SIMPLE AND STEREOSELECTIVE METHOD OF PREPARATION

When treated with two equivalents of a butyllithium/potassium tert-but oxide mixture, terminal olefins carrying unprotected hydroxy or carbox y groups generate allylmetal intermediates which can be trapped with c hlorotrimethylsilane to afford functionalized (Z)-2-alkenyltrimethylsi lanes. One equivalent of the superbasic reagent suffices if the unsatu rated alcohols are first protected as acetals before being subjected t o the metalation/silylation/hydrolysis sequence.