反应详情

In an anhydrous DMF solution (28 mL) containing zinc powder (2.48 g, 37.9 mmol) 1,2-dibromoethane (0.17 mL) is injected under argon. The solution is stirred for 20 min at room temperature. TMSCI (50 μL) is injected and the solution is heated with stirring to 60° C. for 30 min. (R)-methyl 2-(tert-butoxycarbonylamino)-3-iodopropanoate (VIII) (2.0 g, 6.08 mmol) in DMF (8 mL) is added drop wise. The solution is then stirred for 20 min at 60° C. LiCl (587 mg, 13.8 mmol) and CuCN (619 mg, 6.9 mmol) in DMF (6.5 mL) are injected at −55° C. and the solution is placed at 0° C. for 10 min. The latter is again placed at −55° C. and allyl bromide (1.05 mL, 12 mmol) is injected. After 5 min, the solution is placed at 0° C. and stirred for 2 hours at this temperature. The zinc which has not reacted is removed by filtration on celite and the filtrate is treated with a saturated NH4Cl solution. The product is extracted with ethyl acetate (EtOAc). The collected organic phases are washed with a saturated NaCl solution, and then dried on MgSO4 and evaporated. After flash chromatography (silica gel, 8% EtOAc/cyclohexane), the product (IX) (1.38 g, 93%) is isolated as a colorless oil.

1. temperaturethe solution is heated
2. additionis added drop wise
3. stirringThe solution is then stirred for 20 min at 60° C
4. customare injected at −55° C.
5. waitthe solution is placed at 0° C. for 10 min
6. customis again placed at −55° C.
7. waitAfter 5 min
8. customis placed at 0° C.
9. stirringstirred for 2 hours at this temperature
10. customis removed by filtration on celite
11. additionthe filtrate is treated with a saturated NH4Cl solution
12. extractionThe product is extracted with ethyl acetate (EtOAc)
13. washThe collected organic phases are washed with a saturated NaCl solution
14. customdried on MgSO4
15. customevaporated