4-Penten-1-OL → 3-Methyl-N-{[(pent-4-en-1-yl)oxy]carbonyl}-L-valine

Participants

Reaction Conditions

Reaction Steps

A solution of 4-pentenol (7.22 g, 83.8 mmol) and triphosgene (11.3 g, 38.1 mmol) in dioxane (160 mL) was cooled to 0° C. followed by a dropwise addition of DIPEA (9.85 g, 76.2 mL). The white suspension was stirred vigorously for 1 h at 25° C., then cooled to 0° C. A 1 N solution of NaOH (76.2 mL) and t-butylglycine (10.0 g, 76.2 mmol) were added. The resulting suspension was warmed to 25° C. and stirred for 18 h. Approximately half of the dioxane was removed in vacuo, the solution was poured into 1 N NaOH (100 nL) and washed with dichloromethane (3×150 mL). The aqueous layer was acidified with 6 N HCl and the desired product was extracted with dichloromethane (3×150 mL). The combined organics were dried over MgSO4 and concentrated to give 13.7 g (73.9% yield) of 3-methyl-N-[(pent-4-enyloxy)carbonyl]-L-valine as a colorless oil. LRMS (ESI) m/z 244 [(M+H)+; calcd for C12H22NO4: 244].

Provenance & Evidence