. Cl, ); 6- CH 3 s: 1.47; H 3 : d 3.25 (8.5); H 3a d: 3.66 (8.5); H 6 q: 5.13 (1.5); OCH 3 s: 3.38. 13 C NMR 4-CH 3 : 25.4; 5-CH 3 : 11.6; Rearrangement of lactone-ester 3b into lactone-ester 2b. A solution of, mole) in xylene (50 mL) was refluxed for 1 h. Distillation of the solvent under reduced pressure gave practically quantitatively the crude lactone-ester 2b, which recrystallized from petroleum ether. 2b: yield 100%; white crystals, p.118

H. Lactone-3a and . Nmr, 05 mole) in ether was treated by 2 eq of anhydrous diethylamine for 15 min at rt. The solution was then cooled, and the unstable lactone 4a slowly crystallizes. 4a: yield 80%; m.p.: 114°C; ? CO 1770, pp.4-7, 1720.

J. Dillenschneider, L. Dufossé, M. Fouillaud, N. Sutthiwong, R. Labia et al., Applications of Nuclear Magnetic Resonance in Organic Chemistry, press. [2], pp.345-187, 1972.

N. C. Deno and C. Pittman, Aliphatic Dienyl Cations, Journal of the American Chemical Society, vol.86, issue.9, p.1871, 1964.
DOI : 10.1021/ja01063a056