Borane → N-(5-Bromo-2-chlorobenzyl)cyclopropanamine

Participants

Reaction Steps

At 0° C., a suspension of 5-bromo-2-chloro-N-cyclopropylbenzamide from the previous step (1 eq.) in THF (0.4 M) was added borane (1 M THF solution, 3 eq.). The resulting suspension was warmed to RT over 1 h and then heated at reflux for 1 h. The now pale yellow solution was re-cooled to 0° C. and carefully quenched with 1 N aq. HCl. The resulting mixture was heated at reflux for 1 h to ensure complete breakdown of the amine-borane complex. Following careful neutralization with 1 N aq. NaOH, the aqueous layer was separated and back extracted with EtOAc. The combined organic extracts were washed with brine, dried over MgSO4 and filtered. The filtrate was concentrated in vacuo and the crude product thus obtained was purified further by way of column chromatography (SiO2, Hex→80:20 (v/v) Hex:Et2O) to reveal the title compound as a colorless oil.

Provenance & Evidence