ChemInform Abstract: Alkylation of 3-Ethyl-2-methyl-4-oxo-4,5,6,7-tetrahydroindole with Bromoesters: Benzenesulfonyl as Convenient Nitrogen Protecting Group

α-Alkylation of 3-ethyl-2-methyl-4-oxo-1H-4,5,6,7-tetrahydroindole (3) with bromoesters gives 3-ethyl-2-methyl-4-oxo-1H-4,5,6,7-tetrahydro-5-indoleacetate (5a), 3-ethyl-2-methyl-4-oxo-1H-4,5,6,7-tetrahydro-5-indole-2-propionate (5b), and 3-ethyl-2-methyl-4-oxo-1H-4,5,6,7-tetrahydro-5-indole-3-propionate (6)