lithium t-octyl-t-butylamide; triethylamine in tetrahydrofuran T=-78°C; Yield given. Yields of byproduct given;

1,1,1,3,3,3-hexamethyl-disilazane in pentane 1) -10 deg C, 30 min, 2) to r.t., 2 h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

tetrabutyl ammonium fluoride in pentane 1) -25 deg C, 10 min, 2) to r.t., 1 h; Yield given. Yields of byproduct given;

copper dichloride in N,N-dimethyl-formamide 1) r.t., 3 h, 2) 50 deg C, 30 min;