N,N,N',N',N'',N''-hexamethylphosphoric triamide in tetrahydrofuran dropwise addn. under N2 of a freshly prepd. THF/ HMPA soln. contg. 1 molar equiv of lithium diisopropylamide to a soln. of the enolate adduct at -78°C; stirred at room temp. (12 h); poured into 1.5 M HCl; extn. with ether; washed with water, satd. NaCl, dried over MgSO4; evapn. of solvent, chromy. (silica gel, 20percent EtOAc/ pentane);