3a-( H y d r o x y m e t hyl)-2@,6a-dimethyl-l@-( m e t hoxycarbonyl)cyclohexane-2a-carboxylic Acid 7-Lactone (49). A mixture of 47 (40 mg, 0.18 "01) and 5 mg of Adams' catalyst in 3 mL of methanol was stirred under a hydrogen atmosphere until gaa uptake had ceased. Filtration and evaporation of the solvent afforded 40 mg (98%) of 49: IR (film) 2950, 1775,1735 cm-'; 'H NMR (CDC13) 6 4.30 (1 H, d, J = 2 Hz), 4.20 (1 H, d, J = 4 Hz), 3.75 (3 H, s), 2.6-2.2 (2 H, m), 2.35 (1 H, d, J = 11 Hz), 2.1-1.6 (4 H, m), 1.33 (3 H, s), 0.98 (3 H, d, J = 6 Hz); mass spectrum, m/e 226.121 (M+, calcd for C12HlBO4 226.121).trans,trans-2,4-Rexadienyl Tetrolate (51). A solution of tetrolic acid (1.64 g, 20 mmol) and 4 mL of oxalyl chloride in 20 mL of dry benzene was heated to 50 "C for 1 h. Careful concentration in vacuo (20 "C bath) afforded a brown oil. This oil was added slowly to a solution of sorbyl alcohol (19; 1.96 g, 20 mmol) and pyridine (2 mL, 25 mmol) in 20 mL of benzene a t 0 "C. After being stirred at room temperature for 4 h, the mixture waa diluted with ether, and the ethereal layer was washed with saturated CuS04 solution, water, and saturated NaCl solution. The ethereal extracts were dried over MgS04, filtered, and evaporated to give an oil. Column chromatography (30% ethyl acetate-hexane) of this material afforded 1.0 g (50%) of sorbyl alcohol and 1.20 g (42%) of 51: IR (film) 2950,2250,1710,1250 cm-'; 'H NMR (CDCld 6 6.4-5.4 (4 H, m), 4.65 (2 H, d, J = 6 Hz), 1.96 (3 H, s), 1.76 (3 H, d, J = 6 Hz); mass spectrum, m/e 164 (M+). 3a-(Hydroxymethyl)-1,6a-dimethylcyclohexal,4-dienecarboxylic Acid 7-Lactone (52). A solution of 1.20 g (7.3 "01) of 51 and 100 mg of 2,6-di-tert-butyl-p-cresol was refluxed for 24 h under a nitrogen atmosphere. After cooling, the solvent was removed in vacuo to yield 1.25 g (96%) of a light brown oil which was shown by TLC to be virtually pure 52. Column chromatography (30% ethyl acetate-hexane) provided an analytically pure sample of 5 2 IR (Nujol) 1745 cm-'; 'H NMR (CDCl,) 6 6.72 (2 H, s), 4.55 (1 H, dd, J = 7, 7 Hz), 3.75 (1 H, dd, J = 7, 10 Hz), 3.7-3.3 (1 H, m), 3.15-2.75 (1 H, m), 2.21 (3 H, t, J = 1.5 Hz), 1.25 (3 H, d, J = 7 Hz); mass spectrum, m/e 162.069 (M+ -H2, calcd for CloHloOz 162.068). 3a-(Hydroxymethy1)-1,6a-dimethylcyclohex-l-enecarboxylic Acid ?-Lactone (54). A suspension of 50 mg of platinum oxide in 25 mL of ethyl acetate was stirred under a hydrogen atmosphere until hydrogen uptake had stopped, and a solution of 52 (710 mg, 4.3 mmol) in 5 mL of ethyl acetate was added by syringe. Stirring was initiated, and the mixture took up 4.3 mmol of hydrogen over a period of 35 min. At this point, gas uptake slowed, and the reaction mixture was removed from the hydrogen atmosphere and filtered. Evaporation of the solvent in vacuo afforded 685 mg (95%) of 54 IR (film) 2950,2870,1775, 1679 cm-'; ' H NMR (CDClJ 6 4.46 (1 H, dd, J = 8,8 Hz), 3.77 (1 H, dd, J = 8, 10 Hz), 3.1-2.7 (1 H, m), 2.5-2.2 (1 H, m), 2.13 (3 H, d, J = 2 Hz), 2.0-1.6 (4 H, m), 1.12 (3 H, d, J = 7 Hz); mass spec...
