2-Methylquinoline → 2-Methyl-1,2,3,4-tetrahydroquinoline

Participants

Reaction Steps

To 10 ml of methylene chloride, 55.6 mg of a pentamethylcyclopentadienyl iridium(III) chloride dimer ([Cp*IrCl2]2), 16.7 mg of (R)-prolinamide and 15.6 mg of triethylamine were added, and the mixture was stirred under argon atmosphere at room temperature for about 30 minutes to give a catalyst-containing mixture. In 60 ml of methylene chloride, 1.00 g of 2-methylquinoline was dissolved, and a 1/10 amount of the catalyst-containing mixture (equivalent to 0.1 mol % as an iridium chloride dimer) was added. After cooling to −10° C., 8.4 ml of a mixed solvent of formic acid/triethylamine (molar ratio: 5/2) was added dropwise, and the mixture was stirred at the same temperature for 2 days to give 2-methyl-1,2,3,4-tetrahydroquinoline (degree of conversion: 67.4%). The R-enantiomer was in excess and the optical purity was 85.4% ee.

Provenance & Evidence