Dimethylformamide → (R)-8-(benzyloxy)-5-(2-bromo-1-((tert-butyldimethylsilyl)oxy)ethyl)quinolin-2(1H)-one

Participants

Reaction Steps

To the product of step (b) (70.2 g, 189 mmol) was added N,N-dimethylformamide (260 mL) and this mixture was cooled in an ice bath under nitrogen. 2,6-Lutidine (40.3 g, 376 mmol) was added over 5 min and then tert-butyldimethylsilyl trifluoromethanesulfonate (99.8 g, 378 mmol) was added slowly while maintaining the temperature below 20° C. The mixture was allowed to warm to room temperature for 45 min. Methanol (45 mL) was added to the mixture dropwise over 10 min and the mixture was partitioned between ethyl acetate/cyclohexane (1:1, 500 mL) and water/brine (1:1, 500 mL). The organics were washed twice more with water/brine (1:1, 500 mL each). The combined organics were evaporated under reduced pressure to give a light yellow oil. Two separate portions of cyclohexane (400 mL) were added to the oil and distillation continued until a thick white slurry was formed. Cyclohexane (300 mL) was added to the slurry and the resulting white crystals were filtered, washed with cyclohexane (300 mL) and dried under reduced pressure to give the title compound (75.4 g, 151 mmol, 80% yield, 98.6% ee).

Provenance & Evidence