1,8-Diazabicyclo(5.4.0)undec-7-ene → 2-Vinyl-morpholine-2,4-dicarboxylic acid 4-tert-butyl ester 2-methyl ester

Participants

Reaction Conditions

Reaction Steps

A warm (35° C.) solution of 2-(1-trifluoromethanesulfonyloxy-ethyl)-morpholine-2,4-dicarboxylic acid 4-tert-butyl ester 2-methyl ester (1.384 g, 3.284 mmol) in dichloromethane (40 mL) was treated with 1,8-diazabicyclo[5.4.0]undec-7-ene (2.5 mL, 16.422 mmol). After stirring at 35° C. for 2 h, the reaction was cooled to 0° C. and quenched with hydrochloric acid (1 M, 50 mL). The aqueous layer was extracted with dichloromethane. The organics were combined, filtered through a phase separator and the volatiles were removed in vacuo to provide the title compound as an orange oil which was used without further purification in the next step. 1H NMR (300 MHz, CDCl3) δ 1.49 (s, 9H), 3.13-3.29 (m, 2H), 3.60-3.73 (m, 1H), 3.79 (s, 3H), 3.83-3.92 (m, 2H), 4.24 (d, J=13.1 Hz, 1H), 5.37 (d, J=10.9 Hz, 1H), 5.55 (d, J=17.4 Hz, 1H), 5.84 (dd, J=17.4, 10.9 Hz, 1H).

Provenance & Evidence