Toluene → 1-Benzyl-4-[3-(tert-butoxycarbonylamino)-1-fluorocyclobutan-3-yl]-2-pyrrolidone

Participants

Reaction Steps

A 1.79 g (4.96 mmol) portion of 1-benzyl-4-[3-(tert-butoxycarbonylamino)-1-hydroxycyclobutan-3-yl]-2-pyrrolidone (Isomer B2) was dissolved in a mixed solvent consisting of 50 ml of toluene and 20 ml of dichloromethane to which, while cooling in an ice bath with stirring, was then added 1.31 ml (9.92 mmol) of diethylaminosulfur trifluoride, subsequently carrying out 12 hours of stirring at 50° C. While cooling in an ice bath with stirring, the reaction solution was alkalified by slowly adding saturated sodium bicarbonate aqueous solution and then mixed with chloroform to carry out separation of layers, and the resulting organic layer was washed with saturated brine. The aqueous layer was again extracted with chloroform, and the organic layers were combined and dried over anhydrous sodium sulfate. After filtration, the solvent was evaporated under a reduced pressure and the resulting residue was purified by a silica gel column chromatography to give 964 mg (53.6%) of the title compound. 1H-NMR data of the thus obtained compound coincided with the aforementioned data of its enantiomer Isomer B1.

Provenance & Evidence