Hydrochloric Acid → HCID 89793963, compound

Participants

Reaction Steps

Flask B: To a clear solution of Boc-D-abu-oh (Bachem, 5.00 g, 24.60 mmol) in THF (40 mL) at RT under nitrogen was added 1,1′-carbonyldiimidazole (4.19 g, 25.8 mmol) in one portion. Gas evolution observed and the reaction was stirred for 2.5 h at RT. Flask A: To a mixture of mono-tert-butyl malonate (4.17 mL, 27.1 mmol) and anhydrous magnesium chloride (2.58 g, 27.1 mmol) in THF (100 mL) in a 500 mL 3-necked round-bottomed flask in an ice bath was added potassium tert-butoxide (1.0 M in THF, 27.1 mL, 27.1 mmol) slowly dropwise via addition funnel such that the temperature did not exceed 8° C. The resulting white suspension (milk-like) was stirred at RT for 2 h 30 min then the contents of flask B was added to flask A and the reaction mixture was heated at 50° C. overnight (16 h). The reaction mixture was treated with 1N HCl (15 mL) to pH=7 and then treated with Et2O (60 mL) and water (45 mL). The organic layer was separated, and washed brine (30 mL), dried over anhydrous MgSO4, filtered, and concentrated in vacuo to afford (R)-tert-butyl 4-((tert-butoxycarbonyl)amino)-3-oxohexanoate (505a) as a viscous light yellow oil. m/z (ESI, +ve) 324.2 (M+Na)+.

Provenance & Evidence