[C:1]1([CH3:11])[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[CH2:7][C:8]([OH:10])=[O:9].C([Li])CCC.[CH:17]([CH2:19][CH2:20][CH2:21][CH2:22][CH2:23][CH2:24][C:25]([O:27][CH3:28])=[O:26])=[O:18].C(O)(=O)C>C1COCC1.CCCCCC>[C:8]([CH:7]([C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][C:1]=1[CH3:11])[CH:17]([OH:18])[CH2:19][CH2:20][CH2:21][CH2:22][CH2:23][CH2:24][C:25]([O:27][CH3:28])=[O:26])([OH:10])=[O:9]
o-Tolylacetic acid (4.56 g.) in THF (50 ml.) was treated at 5°-10° C. under argon with a 1.6M solution (36.0 ml.) of butyllithium in hexane. After 1 hour the solution obtained was added dropwise to a solution of methyl 7-formylheptanoate (5.68 g.) in dry THF (50 ml.) at -30 ° to -50° C. during 30 minutes. The mixture was stirred for 1.5 hours at the same temperature. Acetic acid (3.5 ml. ) was then added carefully and the mixture was evaporated. The residue was partitioned between ether (100 ml.) and saturated sodium bicarbonate solution (50 ml.). The aqueous layer was acidified to pH 4 (HCl) and extracted thoroughly with ether. The combined extracts were washed with water, dried (MgSO4) and evaporated. The residual oil was purified by medium pressure liquid chromatography on silica (190 g.), eluting with 30% v/v ethyl acetate/hexane, to give methyl 9-carboxy-8-hydroxy-9-o-tolylnonanoate (A) as an oil (1.94 g., single diastereoisomer);NMR : 1-1.7 (10H,m), 2.1-2.5 (5H,m), 3.6 (3H,s), 3.8-4.3 (2H,m), 6.7 (2H,br s), 7.2 (4H,s); m/e (chemical ionisation): 323 (M+ +H), 340 (M+ +NH4).
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