Methyl 2-[(tert-butoxycarbonyl)amino]pent-4-ynoate → HCID 59750578, compound

Participants

Reaction Steps

Compound 22, [4-(4-iodophenyl)-but-3-ynyl]carbamic acid benzyl ester (0.52 g, 1.283 mmol) was dissolved in a mixture of anhydrous THF and triethylamine (8 mL, 1/1, v/v). To the solution was added copper (I) iodide (0.025 g, 0.128 mmol). The mixture was stirred at room temperature for 15 min. The flask was then evacuated and re-filled with Argon. The procedure was repeated three more times to ensure no oxygen remained. The catalyst, dichlorobis(triphenylphosphine)palladium(II) (0.09 g, 0.128 mmol) was added into the mixture under Argon protection. The mixture was further stirred at room temperature for 30 min. The other starting material 23, 2-tert-butoxycarbonylamino-pent-4-ynoic acid methyl ester (0.32 g, 1.412 mmol), dissolved in THF (4 mL) was added dropwise over 15 min. The newly formed reaction mixture was further stirred overnight at room temperature. The solid in the reaction mixture was vacuum filtered. The filtrate was concentrated. The residue was re-dissolved in dichloromethane and purified by column chromatography, eluting with a mixture of ethyl acetate (0-25%) and hexanes (100-75%) to afford the product 24 (0.64 g, 99%) as a gummy, yellowish solid. 1H NMR (300 MHz, CDCl3): δ 1.46 (s, 9H), 2.64 (t, J=6.3 Hz, 2H), 2.95 (t, J=4.1 Hz, 2H), 3.42 (m, 2H), 3.79 (s, 3H), 4.56 (m, 1H), 5.12 (s, 2H), 5.38 (br s, 1H), 7.29 (s, 4H), 7.35 (m, 5H). m/z (APCI) 502 [C29H32N2O6−H]+.

Provenance & Evidence