ammonium chloride (20 mL) and ether (20 mL) and was shaken. The organic layer was separated and was extracted with a saturated solution of sodium bicarbonate (3 X 10 mL). The aqueous layer was acidified with 3 M hydrochloric acid and extracted with ether (3 X 30 mL). The combined ether extract was dried and the solvent was removed in vacuo to give 2.60 g (88%) of 12h as an oil. This material was dissolved in methanol (200 mL) and the solution was stirred for 24 h under one atmosphere of hydrogen with 5% palladium-on-carbon (0.26 g) as catalyst. The suspension was filtered through Celite, and the filtrate was concentrated in vacuo to give 2.4 g (91%) of the saturated acid as an oil. This was dissolved in benzene (200 mL) containing benzoic acid (12 mg), and the solution was refluxed for 24 h under 4Á molecular sieves. After removal of the solvent in vacuo, the residual oil was purified by chromatography (40% ethyl acetate in hexane) to give 1.96 g (85%) of 16:
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