Diisopropylethylamine → 3-(SR)-((4-(N-(4-Nitrobenzyloxycarbonyl)-N-(allyl)amino)piperidin-1-yl)methyl)-4-(SR)-phenylcyclopentan-1-one di-hydrochloride salt

Participants

Reaction Steps

To a solution of (+−)-trans-4-oxo-2-phenylcyclopentanecarboxaldehyde from Step D (327 mg, 1.74 mmol) in 1,2-dichloroethane (20 mL) was added 4-(N-(4-nitrobenzyloxycarbonyl)(N-allyl)amino)piperidine hydrochloride (667 mg, 1.9 mmol) and DIPEA (0.36 mL, 2.1 mmol). After 5 min, sodium triacetoxyborohydride (740 mg, 3.5 mmol) was added and the reaction was stirred at rt for 4 h. The reaction was diluted with methylene chloride, quenched with aq. sodium carbonate and extracted 3 times with methylene chloride. The organic layers were each washed with brine, dried over sodium sulfate, combined and concentrated in vacuo. The residue was purified by FC eluting with a gradient of 35 to 75% ethyl acetate in hexanes to give the title product (365 mg) as the free amine. This was taken up in ether and IM hydrogen chloride in ether (0.5 mL) was added to form the di-hydrochloride salt. The volatiles were removed in vacuo to give the title salt.

Provenance & Evidence