Potassium Bromide → tert-butyl (1S)-1-formyl-2-methylpropyl(methyl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of 10.5 g Boc-N-methyl-valinol (48.3 mmol) in 50 ml dichloromethane was added a solution of 1.63 g NaHCO3 (19.3 mmol) and 0.58 g KBr (4.8 mmol) in 50 ml deionized water. The reaction mixture was cooled to 0° C. and after the addition of 77 mg 2,2,6,6-tetramethyl-piperidin-1-oxyl (TEMPO, 0.48 mmol), 36.6 g 10.3% aqueous sodium hypochlorite (53.1 mmol Cl2) were added under stirring over 2.5 h at 0-5°. After additional stirring for 30 min the excess of NaOCl was destroyed by the addition 38% aqueous sodium bisulfite and the reaction mixture was warmed up to 20°. The aqueous layer was extracted with 50 ml dichloromethane and the organic layers were washed with 50 ml 10% brine and dried (Na2SO4). Removal of the solvent by rotary evaporation afforded 9.9 g (95%) crude product as a light orange oil, [α]D=−130 (CHCl3; c=1). 1H-NMR:

Provenance & Evidence