Reactions of Ketene Acetals J. Org. Chem., Vol. 43, No. 25, 1978 4869 at reflux for 2.25 h. The cooled reaction mixture was diluted with benzene (5 mL), washed, dried, and evaporated. The residue was chromatographed on silica gel with n-hexane-benzene (1: 4) and then with benzene as eluent to afford 271 mg (47%) of 11, which was re-crystallized from benzene-n-hexane to give colorless needles: mp 127-128.5" C (lit. 3 mp 124-125" C); ...
