tert-Butanol → Carbamic acid, N-(2,2-dimethyl-3-oxocyclobutyl)-, 1,1-dimethylethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 2,2-dimethyl-3-oxocyclobutanecarboxylic acid (3.9 g, 27.5 mmol) and TEA (5.75 g, 57 mmol) in toluene (160 mL) was added diphenylphosphoryl azide (11.5 mL, 57 mmol) slowly under cooling in an ice-water bath. The mixture was stirred at 100° C. for 4 h. The reaction mixture was cooled down to room temperature, and tert-butanol (82 mL, 925 mmol) was added. The resulting mixture was refluxed overnight. The reaction mixture was treated with aqueous sodium bicarbonate (150 mL) and the aqueous solution was extracted with ethyl acetate (50 mL×3). The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under vacuum, the residue was purified by silica gel column chromatography (2-7% ethyl acetate in petroleum ether) to afford the title compound (650 mg, 3.05 mmol, 11% yield) as a yellow oil. 1H NMR (300 MHz, CDCl3) δ (ppm) 4.81-4.70 (m, 1H), 4.05-3.93 (m, 1H), 3.37 (dd, J1=18.0 Hz, J2=9.0 Hz, 1H), 2.89 (dd, J1=18.0 Hz, J2=6.9 Hz, 1H), 1.48 (s, 9H), 1.28 (s, 3H), 1.13 (s, 3H).

Provenance & Evidence