To a 0 0C solution of 2-(4-chlorophenyl)-2-methylpropanoic acid (99.3 mg, 0.50 mmol) in THF (2 mL) was added 4-methylmorpholine (60.5 muL, 0.55 mmol). After 10 minutes, isobutyl chloroformate (67.4 muL, 0.52 mmol) was added dropwise over 2 minutes. After 2.5 h, a solution of Compound IA (72.3mg, 0.50 mmol) in THF (3 mL) was added dropwise over 2 minutes. After 10 minutes the <n="62"/>cooling bath was removed and the reaction mixture was warmed to room temperature. After 3 h at room temperature, water (5 mL) and ethyl acetate (10 mL) were added, and the resulting mixture was stirred for 10 minutes. At the conclusion of this period, the organic phase was separated, dried over Na2SO4, and then concentrated in vacuo to yield a residue. The residue was purified by flash chromatography (SiC^ , 0-100% ethyl acetate / hexanes) to provide compound IB, which was used directly in the preparation of compound 1C set forth below. LC/MS (m/z) = 325 (M+H)+.
With 2,4,6-trimethyl-pyridine; tetrabutylammonium perchlorate; silver perchlorate; In dichloromethane; at 20℃; for 3h;Electrolysis; Molecular sieve;
General procedure: With no precautions to exclude air or moisture, the ElectraSyn vial (5 ml) with a stir bar was charged with carboxylic acid (0.2 mmol, 1.0 equiv.), alcohol (0.6 mmol, 3.0 equiv.), 2,4,6-collidine (0.6 mmol, 3.0 equiv.), nBu4NPF6 (0.3 mmol, 1.5 equiv.), 3 A molecular sieves (150 mg), AgPF6 (0.3 mmol, 1.5 equiv.) and CH2Cl2 (3.0 ml). The ElectraSyn vial cap equipped with anode (graphite) and cathode (graphite) were inserted into the mixture. After pre-stirring for 15 min, the reaction mixture was electrolysed at a constant current of 10 mA for 3 h. The ElectraSyn vial cap was removed, and electrodes were rinsed with Et2O (2 ml), which was combined with the crude mixture. Then, the crude mixture was further diluted with Et2O (30 ml). The resulting mixture was washed with 2 M HCl (20 ml) and NaHCO3 (aq.) (20 ml), dried over Na2SO4 and concentrated in vacuo. The crude material was purified by preparative thin-layer chromatography to furnish the desired product. Full experimental details and characterization of new compounds can be found in the Supplementary Information.