反应详情

Procedure for the N-alkylation of S2: To a solution of isoxazolidine S1 (2.29 g, 11.49 mmol, 1 eq) in THF (109 mL) were added DMAP (0.07 g, 0.58 mmol, 0.05 eq), Et3N (2.24 mL, 16.09 mmol, 1.4 eq), and TBSOTf (3.70 mL, 16.09 mmol, 1.4 eq) to protect the primary alcohol in 97% yield following purification by flash chromatography (9:1 hexanes/EtOAc). To a solution of TBS-protected isoxazolidine S2 (0.17 g, 0.53 mmol, 1 eq) in DMF (2 mL) was added i-Pr2NEt (0.28 mL, 1.59 mmol, 3 eq) and BnBr or tert-butylbromoacetate (2.64 mmol, 5 eq). The reaction mixture was irradiated in a 1000 W microwave (5×15 s) @ 30% power with mixing between each interval. Once the reaction was complete by TLC analysis, the reaction was diluted with H2O (15 mL), and extracted with Et2O (3×15 mL). The combined organic extracts were washed with H2O (1×20 mL), brine (1×20 mL), dried over Na2SO4, filtered, and concentrated in vacuo.

1. custompurification by flash chromatography (9:1 hexanes/EtOAc)
2. customThe reaction mixture was irradiated in a 1000 W microwave (5×15 s)
3. additionwith mixing between each interval
4. extractionextracted with Et2O (3×15 mL)
5. washThe combined organic extracts were washed with H2O (1×20 mL), brine (1×20 mL)
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated in vacuo