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

Participants

Reaction Conditions

Reaction Steps

DIPEA (9.85 g, 76.2 mmol) was added dropwise to a 0° C. solution of 4-penten-1-ol (7.22 g, 83.9 mmol) and triphosgene (11.3 g, 38.1 mmol) in 160 mL dioxane. The resulting white suspension was stirred for 5 minutes at 0° C., then allowed to warm to 25° C. over 1 hour. The suspension was cooled to 0° C. with an ice bath and 1 N NaOH (76.2 mL) and L-t-butylglycine (10.0 g, 76.2 mmol) were added. The reaction mixture was warmed to 25° C. and stirred for 18 hours. The dioxane was removed in vacuo and the reaction mixture was basified to pH 12 with 1 N NaOH. The aqueous layer was extracted with DCM (3×150 mL), then acidified to pH˜1 with 6 N HCl. The aqueous layer was extracted with DCM (3×150 mL). The combined organic layers were dried over MgSO4 and concentrated to give the compound as a tan oil (13.7 g, 73.9% yield). LRMS (ESI) m/z 244 [(M+H)+; calcd for C12H22NO4 244].

Provenance & Evidence