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 (1.0 equiv.) and triethylamine (1.5 equiv.) in toluene (0.2 M) was added diphenylphosphoryl azide (1.5 equiv.) slowly at 0° C. The mixture was then stirred at 100° C. for 4 h. The reaction mixture was cooled to room temperature, and tert-butanol (2.5 equiv.) was added. The resulting mixture was then refluxed for 15 h. After reaction completion, aqueous solution of sodium bicarbonate was added, and the mixture was extracted with ethyl acetate, the organic layer was washed with aqueous solution of sodium bicarbonate and brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under vacuum, the residue was purified by silica gel column chromatography (7% ethyl acetate in petroleum ether) to afford the title product (16% yield). 1H NMR (300 MHz, CDCl3) δ (ppm) 4.79 (br, 1H), 4.03-4.01 (m, 1H), 3.43 (dd, J1=18.0 Hz, J2=9.0 Hz, 1H), 2.94 (dd, J1=18.0 Hz, J2=6.9 Hz, 1H), 1.48 (s, 9H), 1.28 (s, 3H), 1.13 (s, 3H).

Provenance & Evidence