Diisopropylethylamine → tert-butyl (2R)-3-(benzyloxy)-1-(2-methyl-1-oxo-4-phenyl-2,7-diazaspiro[4.5]decan-7-yl)-1-oxopropan-2-ylcarbamate

Participants

Reaction Steps

A mixture comprising (R)-3-(benzyloxy)-2-(tert-butoxycarbonylamino)propanoic acid (Sigma-Aldrich) (1.052 g, 3.56 mmol) and ®T3P (50% in EtOAc) (4.16 ml, 7.12 mmol) in MeCN (20 mL) was treated dropwise with DIPEA (2.488 ml, 14.25 mmol). The resulting solution was stirred at room temperature for 30 minutes, then a racemic mixture of (4R,5S)-2-Methyl-4-phenyl-2,7-diazaspiro[4.5]decan-1-one and (4S,5R)-2-Methyl-4-phenyl-2,7-diazaspiro[4.5]decan-1-one (Intermediate 1A) (1 g, 3.56 mmol) was added portionwise. The reaction mixture was stirred for 20 hours at room temperature. The reaction mixture was diluted with 0.1M HCl (20 mL) and extracted with DCM (20 mL). The aqueous phase was further extracted with DCM (3×20 mL). The combined organic portions were washed with a saturated solution of sodium bicarbonate (20 mL), water (20 mL), dried (MgSO4), and concentrated in vacuo to afford the title compound. No purification was performed on the title compound.

Provenance & Evidence