Allyl bromide → Boc-L-Homoallylglycine Methyl ester

Participants

Reaction Steps

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.

Provenance & Evidence