Aspidospermidine-3-carboxylic acid, 4-(acetyloxy)-6,7-didehydro-3-hydroxy-16-methoxy-1-methyl-, methyl ester, (2beta,3beta,4beta,5alpha,12beta,19alpha)- → Indole dihydroindole

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Reaction Steps

Using the procedure of Example 25, 0.522 g (0.887 mmol) of 4,2'-PARF methyl 3-benzyl-1,2,3,3a,4,5-hexahydro-4-[2-p-toluenesulfonyloxymethyl) propyl]-7H-pyrrolo (2,3-d)-carbazole-6-carboxylate on reaction with 0.141 g (1.29 mmol) of t-butyl hypochlorite and 0.136 g ((0.187 mL) of triethylamine in 25 mL of dichloromethane, followed by a reaction with 0.297 g (0.654 mmol) of vindoline, 0.204 g (1.29 g mmol) of tetrafluoroboric acid diethyl ether complex and 0.245 g (1.26 mmol) of silver tetrafluoroborate in 6 mL of acetone, followed by reduction with 0.453 g (8.42 mmol) of potassium borohydride in 15 mL of acetic acid gave 0.276 g (41%) of the more polar 7R indole-indoline product, eluted on centrifugal chromatography with ether/acetone/triethylamine, 100:20:2, and 0.264 g(39%) of the less polar 7S indole-indoline product, eluted with ethyl acetate/ethanol/triethylamine 95:5:1.

Provenance & Evidence