under nitrogen for 15 h. The solvent was evaporated, and the product mixture was chromatographed on silica gel with 5% ether-hexane as an intial eluent. The first fraction afforded a mixture of 13 and 14 that was Separated on GC. The first product was 13 (0.41 g, 21%): IR (film) 2940 (C-H), 1670, 810 cm'1 (C=CH); NMR 5 5.31 (t, 1,2 ), 2.6-1.4 (m, 6,3 H, 4 H, and 5 ), 1.3, 1.25, 1.00, 0.95, 0.90 (s, 3 each, five methyls); mass spectrum, m/e (rel intensity) 178 (M+, 28) 163 ( -CH3, 7), 135 (100), 121 (7), 119 (7), 107 (35), 96 (35), 93 (38), 91 (15), 81 (34), 79 (22); high-resolution mass spectrum calculated for Ci3H22 178.1724, found 178.1735. The second product was 1-isopropenyl-6-isopropyl-6-methylcyclohexene (14) (0.17 g, 9%): NMR 5.57 (t, 1, 2 H), 4.73 (m, 2, isopropenyl olefinic protons), 1.88 (s, 3, isopropenyl methyl), 1.2 (S, 3,6-methyl), 0.85, 0.78 (d, 3 each, isopropyl methyls); UV (MeOH) Xw,.. 228 nm (< 8080); mass spectrum, m/e (relative intensity), 178 (M+, 15), 165 (7), 135 (100), 119 (28), 107 (47), 105 (11), 93 (49), 91 (31); high-resolution mass spectrum calculated for C13H22 178.1724, found 178.1725.Further elution afforded starting material 11 (1 g, 50%) and finally 12 (0.12 g, 6%):
