反应详情

A solution of 4-bromo-2-chloroanisole (3 g, 13.55 mmol) and (S)-benzyl (1-(methoxy(methyl)amino)-1-oxopropan-2-yl)carbamate (3.79 g, 14.22 mmol) in THF (33.9 mL) was cooled to −20° C. with dry ice/acetone. To this solution was added isopropylmagnesium chloride lithium chloride complex (22.9 mL, 29.8 mmol) at −20° C. dropwise under N2. After addition, the reaction mixture was warmed up to rt and stirred overnight. The reaction mixture was cooled to −40° C. and slowly poured into a stirred mixture of crushed ice and 30 mL of 1N HCl. The resulting mixture was diluted with 30 mL of brine, extracted with EtOAc (3×50 mL). The organic layer was dried with Na2SO4 and concentrated. The residue was purified by silica gel chromatography, eluted with 0-100% EtOAc in hexane to give (S)-benzyl (1-(3-chloro-4-methoxyphenyl)-1-oxopropan-2-yl)carbamate (0.82 g) as a white solid. 1H NMR (500 MHz, CDCl3): δ 8.05 (s, 1H), 7.92 (d, 1H), 6.98 (d, 1H), 5.93 (d, 1H), 5.29 (m, 1H), 5.16 (s, 2H), 3.99 (s, 3H), 1.43 (d, 3H).

1. additionAfter addition
2. temperatureThe reaction mixture was cooled to −40° C.
3. extractionextracted with EtOAc (3×50 mL)
4. dry with materialThe organic layer was dried with Na2SO4
5. concentrationconcentrated
6. customThe residue was purified by silica gel chromatography
7. washeluted with 0-100% EtOAc in hexane