Boron tribromide → (3aS-cis)-1,2,3,3a,8,8a-hexahydro-1-(2-phenylethyl)-3a, 8-dimethylpyrrolo[2,3-b]indol-5-ol

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Reaction Steps

To a stirred solution under nitrogen of 3.22 g of (3aS-cis)-1,2,3,3a,8,8a-hexahydro-5-methoxy-1-(2-phenylethyl)-3a,8-dimethylpyrrolo[2,3-b]indole in 50 ml of degassed chloroform is added dropwise at 0° C. a solution of 10.1 g of boron tribromide in 50 ml of degassed chloroform. The mixture is stirred for about 3 days at room temperature, cooled to 0° C. and cautiously quenched by the dropwise addition of water. The mixture is stirred vigorously for 0.5 hour, and a sufficient volume of saturated aqueous sodium bicarbonate solution is added to make the system just basic to a pH paper. The organic phase is separated, dried over anhydrous sodium sulfate and concentrated. The residue is Kugelrohr distilled at 0.1 mm Hg at an oven temperature of 160°-200° to provide pure (3aS-cis)-1,2,3,3a,8,8a-hexahydro-1-(2-phenylethyl)-3a,8-dimethylpyrrolo[2,3-b]indol-5-ol.

Provenance & Evidence