Methyl chloroformate → 1-Tert-butyl 7-methyl indoline-1,7-dicarboxylate

Participants

Reaction Conditions

Reaction Steps

1,1-dimethylethyl 2,3-dihydro-1H-indole-1-carboxylate (5 g, 22.8 mmol) and N,N,N′,N′-tetramethyl-1,2-ethanediamine (4.6 mL, 30.5 mmol) was dissolved in dry diethyl ether (300 mL) and cooled to −78° C. in an acetone/dry ice bath. Sec-butyl lithium (1.4 M solution in cyclohexanes, 17.6 mL, 24.6 mmol) was added dropwise over 10 minutes and the reaction left stirring for 90 minutes at this temperature. Methyl chloroformate (8.8 mL, 10.8 g, 0.1 mol) was added to the mixture and the reaction was allowed to warm up to room temperature over 1 hour. Water was added carefully to the mixture and the organic layer separated and washed 3 times with more water. The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo to give the title compound (4.91 g) as a gummy yellow solid.

Provenance & Evidence