4,5,6,7-tetrahydro-1H-indole-2-carbaldehyde → 2,5,5-Trimethyl-4,5,6,7-tetrahydroindole

Participants

Reaction Steps

Using a procedure closely analogous to the preparation of 4,5,6,7-tetrahydroindole-2-carboxaldehyde, 3,5,5-trimethyl-4-oxo-4,5,6,7-tetrahydroindole 1.65 g (9.31 mmol) was reduced by 36-hour reflux with lithium aluminum hydride 2.0 g in anh. THF (100 mL) to provide 1.50 g (98%) of 2,5,5-trimethyl-4,5,6,7-tetrahydroindole (light tan crystalline solid) that was formylated with a mixture of anhydrous DMF 20 mL and POCl3 1.5 mL to provide the title aldehyde product 1.669 g (93% overall) as a tan solid. 1H-NMR (d6-DMSO, 400 MHz): 11.31 (br s, 1H), 9.43 (s, 1H), 2.51 (m, 2H), 2.14 (s, 3H), 2.13 (s, 2H), 1.49 (t, 6.6 Hz, 2H), 0.94 (s, 6H)

Provenance & Evidence