反应详情

To a stirred solution of oxalyl chloride (2.93 g, 0.0231 mol) in CH2Cl2 (30 mL) at −60° C. was added DMSO (3.6 g, 0.0462 mol) during which the reaction temperature rose up to −55° C. The reaction mixture was stirred at this temperature for 10 min. before the addition of a solution of the methyl N-(tert-butoxycarbonyl)-2-methylserinate product of Example 1b (2.7 g, 0.01157 mol) in CH2Cl2 (20 mL) at −60° C. The reaction mixture was stirred for additional 20 min., quenched with Et3N (5.85 g, 0.0578 mol) between −60° C. to −30° C. and filtered. DI water (50 mL) and EtOAc (100 mL) were added to the filtrate and the layers were separated. The organic layer was dried over anhydrous MgSO4, filtered through Celite and concentrated on a rotovap to give the crude product as an yellow oil. This material was purified by column chromatography using 30% EtOAc in hexane as eluent to give the title product (yield 1.39 g, 49%).

1. customrose up to −55° C
2. filtrationfiltered
3. additionDI water (50 mL) and EtOAc (100 mL) were added to the filtrate
4. customthe layers were separated
5. dry with materialThe organic layer was dried over anhydrous MgSO4
6. filtrationfiltered through Celite
7. concentrationconcentrated on a rotovap
8. customto give the crude product as an yellow oil
9. customThis material was purified by column chromatography