882 cm'1 (m); UV 268 nm (e 9.6 X 103); mass spectrum, m/z = 148.0887 (M+, caled for C10H12O 148.0889).3-(3-Butenyl)cyclopent-2-enone (32). Following the procedure described above for the preparation of 11, the alcohol obtained from 3-butenylmagnesium bromide and cyclopent-2-enone (5.0 g, 61 mmol), after treatment with acidic Cr03, gave 32 (1.403 g, 17% overall), bp 110-115 °C (10 mm); further purification was achieved by preparative VPC on column D (175 °C): NMR (60 MHz) 6.13-5.47 (m, 1 H), 5.83 (dd, J = 1,1 Hz, 1 H), 5.22-4.8 (m, 2 ), 2.72-2.10 (m, 8 H); IR 3070 (w), 2955 (m), 1715 (s), 1672 (w), 1643 (m), 1617 (s), 1435 (m), 981 (m), 910 cm"1 (m); mass spectrum, m/z 136.0887 (M+, caled for C9H120 136.0887).Photolysis of 32. A solution of 32 (176 mg) in CeH6 (67 mL) was irradiated at 25 °C through an uranium glass filter for 10 days.VPC analysis on column G (178 °C) indicated two components and a considerable amount (~40%) of 32 remaining. After preparative VPC, a NMR spectrum of the first component indicated it was a mixture. Further separation was achieved on column H (150 °C); the first eluted component was identified as 14b: NMR (220 MHz) 2.