tert-Butanol → tert-Butyl 1-(4-cyanobenzyl)azetidine-3-carboxylate

Participants

Reaction Steps

To a mixture of 1-(4-cyanobenzyl)azetidine-3-carboxylic acid (3.25 g, 15.0 mmol), DMAP (1.84 g, 15.0 mmol), and tert-butanol (14.1 mL, 150 mmol) in dichloroethane (150 mL) was added EDCI (4.32 g, 22.5 mmol), and the reaction mixture was allowed to stir over the weekend. The volatiles were removed under reduced pressure, and the residue was partitioned between ethyl acetate (250 mL) and a saturated aqueous solution of sodium bicarbonate (250 mL). The organic layer was washed with water (250 mL), washed with brine (100 mL), and dried over anhydrous magnesium sulfate. Concentration under reduced pressure afforded a light yellow oil which was chromatographed on a 5×15 cm silica gel column, eluting with a 0-40% ethyl acetate/hexane gradient to give tert-butyl 1-(4-cyanobenzyl)azetidine-3-carboxylate (3.5 g, 12.9 mmol, 86% yield) as a colorless liquid. HPLC retention time=1.38 minutes−Column: YMC-Combi 4.6×50 mm S-5 ODS column) eluting with 10-90% aqueous methanol+0.2% phosphoric acid over a 4 minute gradient. MS: (M+H)=273.18. 1H NMR (400 MHz, CDCl3) δ ppm 1.46 (s, 9H), 3.26 (m, 3H), 3.52 (m, 2H), 3.66 (s, 2H), 7.39 (d, J=8.3 Hz, 2H), and 7.60 (d, J=8.3 Hz, 2H).

Provenance & Evidence