Boron trifluoride etherate → 2-Benzyl-6-nitro-1,2,3,4-tetrahydroisoquinoline

Participants

Reaction Conditions

Reaction Steps

To a suspension of sodium borohydride (2.13 g, 56.2 mmole) in THF (56 mL) at 0° C. was added boron trifluoride etherate (9 mL, 73 mmole) dropwise. After stirring the contents for 1 hr., dione (16) (5.0 g, 16.9 mmole) in THF (150 mL) was added at 0° C. over a period of 1.5 hr. The contents were warmed to 25° C. for 30 min. and then refluxed for 16 hr. The completed reaction was cooled to 0° C. and cautiously quenched with aqueous 1N sodium hydroxide (75 mL, 75 mmole) while maintaining the temperature at approximately 9° C. The quenched reaction was stirred for 30 min. at 0° C., 1 hr. at 25° C., 50° C. for 18 hrs. and then cooled to 20° C. The solvents were removed under vacuum, ethyl acetate (100 mL) was added and the layers separated. The organic layer was washed with brine, treated with sodium sulfate and the solvents removed under vacuum to afford 4.73 g of a light brown oil which was of sufficient purity to employ in the next step.

Provenance & Evidence