Diisopropylethylamine → tert-butyl (4R)-7,10,10,11,11-pentamethyl-4-(2-methyl-1-oxo-4-phenyl-2,7-diazaspiro[4.5]decane-7-carbonyl)-6-oxo-1-phenyl-2,9-dioxa-5-aza-10-siladodecan-7-ylcarbamate

Participants

Reaction Steps

A mixture comprising 2-(tert-butoxycarbonylamino)-3-(tert-butyldimethylsilyloxy)-2-methylpropanoic acid (intermediate from step 1) (311 mg, 0.934 mmol) and DIPEA (0.652 ml, 3.73 mmol) in DMF (5 mL) was treated with a solution of ®T3P (50% in EtOAc) (1.090 ml, 1.867 mmol) dropwise at room temperature. The resulting solution was stirred for 15 minutes, then 7-((R)-2-amino-3-(benzyloxy)propanoyl)-2-methyl-4-phenyl-2,7-diazaspiro[4.5]decan-1-one (intermediate from step 3) (500 mg, 0.934 mmol) in DMF (1 mL) was added dropwise at room temperature. The reaction mixture was stirred for 20 hours. The reaction mixture was diluted with 0.1M HCl (10 mL) and extracted with DCM (3×10 mL). The combined organic portions were washed with a saturated solution of sodium bicarbonate (10 mL), brine (10 mL), water (10 mL) and concentrated in vacuo. Purification of the crude product by chromatography on silica eluting with 0-70% EtOAc/iso-hexane afforded the title compound.

Provenance & Evidence