Abstract
Photoreaction of diketene with 3-acetoxy-5, 5-dimethyl-2-cyclohexenone (1) gives 6-acetoxy-7-hydroxy-4, 4-dimethyl-cis-bicyclo [4.2.0] octan-2-one-7-acetic acid β-lactone (2 and 3). Treatment of 2 with dimethylamine affords 3-acetoxy-7-hydroxy-N, N, 4, 4-tetramethyl-cis-bicyclo [4.2.0] octan-2-one-7-acetamide (4), while similar treatment of 3 affords 1-acetoxy-N, N, 4, 4-tetramethylcyclooctane-2, 6-dione-1-acetamide (5). This result suggests the spiro-configuration of 2 is the trans (acetoxy and oxetane O), while that of 3 being the cis.
