5-Bromoindole → (R)-5-Bromo-3-(1-methyl-2-pyrrolidinyl methyl)-1H-indole

Participants

Reaction Steps

European Patent No. 0592438 describes the preparation of eletriptan by the catalytic reduction of (R)-5-(2-benzenesulphonylethenyl)-3-(N-methylpyrrolidin-2-ylmethyl)-1 H-indole, which compound is prepared by (i) reacting N-benzyloxycarbonyl-D-proline acid chloride with 5-bromoindole in the presence of a Grignard reagent, (ii) reducing the resulting (R)-3-(N-benzyloxycarbonylpyrrolidin-2-ylcarbonyl)-5-bromo-1H-indole to give (R)-5-bromo-3-(N-methylpyrrolidin-2-ylmethyl)-1H-indole and (iii) reacting same with phenyl vinyl sulphone in the presence of a palladium catalyst, a triarylphosphine and a base.

Provenance & Evidence