Hydrochloric Acid → 2-(1-Ethenyl-3,3,5,5-tetramethylcyclohexyl)acetic acid

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Reaction Steps

A solution of NaOH (1.03 g, 25.8 mmol) and acetate 16 (1.3 g, 5.15 mmol) in methanol (26 ml) was refluxed for 3 h. The mixture was cooled to room temperature and poured into water (100 ml). The aqueous phase was acidified by conc. aqueous HCl and extracted with hexane (330 ml). The combined organic phases were washed with brine and dried over CaCl2, filtered and evaporated. The residue was purified by flash chromatography on silica gel (light petroleum ether-ethyl acetate, 10:1) to give 17 (0.7 g, 71%) as a colorless solid with m.p. 92-94° C. 1H-NMR (CDCl3, TMS): 0.92 (6H, s, 3,5-CH3); 1.02 (6H, s, 3,5-CH3); 1.00-1.30 (4H, m, 4-CH2 and 2,6-CH); 1.90 (2H, d, 14 Hz, 2,6-CH); 2.27 (2H, s, CH2C═O); 5.11 and 5.13 (total 2H, both d, 11 and 18 Hz, ═CH2); 5.99 (1H, dd, 18 and 11 Hz, ═CH) and 10.80 ppm (1H, br s, COOH).

Provenance & Evidence