... The reaction mixture was stirred for 1 h at -25 OC and kept overnight at room temperature; saturated aqueous NH4C1 was then added, and the organic layer was washed with 1 N HC1 (15 mL) and saturated brine (15 mL). ... Page 2. 3638 J. Org. Chem., Vol. 56, No. 11, 1991 ...