Triethylamine → HCID 9858056, compound

Participants

Reaction Steps

3 mL of triethylamine was added to a solution of 5 g of compound 7a in 200 mL of tetrahydrofuran at room temperature. The solution was stirred for 60 min at room temperature and then was moved to a −78° C. dry ice acetone bath. To this solution was added dropwise 2.6 mL of iso-butyl chloroformate. The suspension was stirred from −78° C. to room temperature overnight. The mixture was filtered through a celite and silica gel pad, and washed with small amount tetrahydrofuran. To this solution in an ice bath was added 2.0 g of sodium borohydride, followed by dropwise addition of 10 mL of water. Carbon dioxide gas evolved violently. The reaction mixture was stirred for 2-4 hr, and was filtered through a celite pad. After the solvent evaporated, the aqueous layer was extracted several times with ethyl acetate. The organic layer was combined, washed with brine, dried over magnesium sulfate, and concentrated. The solid was recrystallized from ethyl acetate and hexanes to form the title compound as a colorless solid (80% yield, 95% de): mp 170.0-170.5° C.; [α]25D=−86.4 (c 1.0, CH3OH); 1H NMR (200 MHz, CDCl3) δ 7.40-7.10 (m, 7 H), 6.98 (t, J=8.7Hz, 2 H), 5.51 (br d, J=7.7 Hz, 1 H), 5.00 (quint, J=7.4 Hz, 1 H), 3.60-3.50 (m, 2 H), 3.33 (m, 1 H), 2.55 (dd, J=6.6, 14.2 Hz, 1 H), 2.38 (dd, J=8.6, 14.2 Hz, 1 H), 1.95-1.75 (m, 2 H), 1.27 (d, J=6.9 Hz, 3 H); 13C NMR (125 MHz, CDCl3) δ 170.6, 161.6, 142.9, 139.6, 128.9, 128.6, 127.4, 126.1, 115.4, 60.1, 48.6, 44.0, 38.9, 38.4, 21.3. Anal. Calcd for C19H22FNO2: C, 72.36; H, 7.03; N, 4.44. Found: C, 72.35; H, 6.83; N, 4.33.

Provenance & Evidence