A novel synthesis of beta-ketosilanes via organoboranes

A convenient, novel synthesis of beta-ketosilanes based on (Z)-1-bromo-1-al kenylboronate esters is developed. alpha-Bromo-(Z)-1-alkenylboronate esters readily available using literature procedures smoothly undergo a reaction with trimethylsilylmethyllithium in tetrahydrofuran to provide the correspo nding 'ate' complexes. These 'ate' complexes will undergo intramolecular nu cleophilic substitution reactions to afford the corresponding (E)-trisubsti tuted olefins containing trimethylsilylmethyl moiety. The oxidation of thes e intermediates with sodium acetate and hydrogen peroxide provides beta-ket osilanes in good yields (63-75% yield). (C) 2000 Elsevier Science Ltd. All rights reserved.