Aluminum(III) Chloride → ethyl 2-bromo-7-ethyl-7,8-dihydro-4H-thieno[2,3-d]azepine-6(5H)-carboxylate

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Reaction Steps

Aluminum chloride (972.2 mg, 7.291 mmol) was added to DCM (60 mL) at 0° C., followed by addition of borane-tert-butylamine complex (1.268 g, 14.58 mmol). To the mixture was added a solution of Compound 1037 (650 mg, 2.431 mmol) in DCM (5 mL). The reaction was allowed to warm up to RT and stirred for 18 hours, followed by quenching the reaction with 2N HCl solution until gas evolution ceased. The mixture was extracted with DCM, dried over Na2SO4, and the volatiles removed under reduced pressure. The resulting residue (Compound 1038) was dissolved in acetonitrile and N-Bromosuccinamide (432.7 mg, 2.431 mmol) was added dropwise. The reaction mixture was stirred at RT for 1 hour, then concentrated under vacuum. The residue was purified by silica gel chromatography, using a 0-20% EtOAC/hexanes gradient as eluant, to give ethyl 2-bromo-7-ethyl-7,8-dihydro-4H-thieno[2,3-d]azepine-6(5H)-carboxylate (Compound 1039, 300 mg).

Provenance & Evidence