N1CCOCC1.[CH:7]1([CH:10]2[CH:15]=[CH:14][C:13]3=[C:16]([C:24](OC)=[O:25])[CH:17]=[C:18]([O:22][CH3:23])[C:19]([O:20][CH3:21])=[C:12]3[O:11]2)[CH2:9][CH2:8]1.[OH-].[Na+]>C1(C)C=CC=CC=1>[CH:7]1([CH:10]2[CH:15]=[CH:14][C:13]3=[C:16]([CH:24]=[O:25])[CH:17]=[C:18]([O:22][CH3:23])[C:19]([O:20][CH3:21])=[C:12]3[O:11]2)[CH2:8][CH2:9]1A solution of 48 ml of morpholine in 50 ml of toluene was added dropwise over 1 hr. under argon to an ice-cold solution of 143 ml of sodium dihydrido-bis-(2-methoxyethoxy) aluminate (3.5M in toluene) diluted with 200 ml of toluene. The resulting reduction solution was then added dropwise under argon during 1 hr. to a solution, cooled to -35° C., of 46 g of methyl (RS)-2-cyclopropyl-7,8-dimethoxy-2H-1-benzopyran-5-carboxylate in 200 ml of toluene and the mixture was stirred at -15° C. for a further 4 hrs. The reaction was stopped by the cautious addition of 40 ml of 3N NaOH and the mixture was left to warm. Extraction: 3×600 ml of ice-water, 1×600 ml of toluene. Chromatography: silica gel, hexane/ethyl acetate 5:1. Crystallization from diethyl ether/ hexane. (RS)-2-Cyclopropyl-7,8-dimethoxy-2H-1-benzopyran-5-carbaldehyde was obtained as a solid.
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