Boron tribromide → (3aS-cis)-1,2,3,3a,8,8a-hexahydro-1-(2-phenylethyl)-3a, 8-dimethylpyrrolo[2,3-b]indol-5-ol
Reaction equation
C[O:2][C:3]1[CH:4]=[C:5]2[C:9](=[CH:10][CH:11]=1)[N:8]([CH3:12])[C@H:7]1[N:13]([CH2:16][CH2:17][C:18]3[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=3)[CH2:14][CH2:15][C@@:6]21[CH3:24].B(Br)(Br)Br>C(Cl)(Cl)Cl>[C:18]1([CH2:17][CH2:16][N:13]2[C@@H:7]3[N:8]([CH3:12])[C:9]4[C:5]([C@:6]3([CH3:24])[CH2:15][CH2:14]2)=[CH:4][C:3]([OH:2])=[CH:11][CH:10]=4)[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
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.