silica gel 1) 25 deg C, 16h, 2) 25 to 120 deg C, 6mm Hg;

potassium hexamethylsilazane in tetrahydrofuran 1.) r.t., 5 min, 2.) -78 deg C --> r.t.; 100 deg C, 30 min; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

potassium hexamethylsilazane in tetrahydrofuran 1.) r.t., 5 min, 2.) -78 deg C --> r.t.; 100 deg C, 30 min; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

potassium hexamethylsilazane in tetrahydrofuran 1.) r.t., 5 min, 2.) -78 deg C, 5 min; r.t., 2 h; other phosphonium salts, other conditions; Product distribution;