4-Methylmorpholine → [2-(Methoxymethyl-carbamoyl)-ethyl]-carbamic acid tert-butyl ester

Participants

Reaction Steps

A solution of BOC-beta-alanine (20 g, 105 mmol), 10-2 (10.3 g, 105 mmol), BOP reagent (46.5 g, 105 mmol), and N-methylmorpholine (46 mL, 420 mmol) in acetonitrile (500 mL) was stirred for 15 h. The reaction was diluted with EtOAc, washed with H2O, 10% KHSO4(aq.), sat. NaHCO3, dried (MgSO4) and concentrated to give crude [2-(methoxymethyl-carbamoyl)-ethyl]-carbamic acid tert-butyl ester 10-3 as a yellow oil. TLC Rf=0.42 (silica, 20% EtOAc/hexanes). To a solution of this crude amide in THF (500 mL) at 0° C. was added CH3MgBr (100 mL of 3M in ether, 300 mmol) over 30 minutes. After 2 h, 10% KHSO4(aq.) was added, the mixture warmed to 25° C., and diluted with EtOAc. The organics were washed with sat. NaHCO3, dried (MgSO4) and concentrated. Flash chromatography (silica, 20% EtOAc/hexanes) gave 10-4 as a yellow oil.

Provenance & Evidence