反应详情

To a solution of a 55/45 diastereoisomeric mixture of pentafluorophenyl (2S)-2-[(4S)-2,2-dimethyl-5-oxo-1,3-dioxolan-4-yl]-4-methylpentanoate and pentafluorophenyl (2R)-2-[(4S)-2,2-dimethyl-5-oxo-1,3-dioxolan-4-yl]-4-methylpentanoate (Intermediate 1, 792.6 mg; 2.0 mmol; 1.0 eq.) in DMF (15 mL) was added 1-(2-pyridyl)piperazine (326.5 mg; 2.0 mmol; 1.0 eq.). After 14 h of reaction at RT, the solvent was evaporated to give an oil. Purification by chromatography (SiO2) gave the title compound as a colorless oil (as a mixture of 2 diastereoisomers 50/50). This product was dissolved on iPrOH (10 mL) at kept at −20° C. for 48 h. The supernatant was collected and evaporated to give a colorless oil (301 mg, 40%, single diastereoisomer). M+(ESI): 3763. HPLC (Condition A): Rt: 5.0 min (HPLC purity: 77.1%). 1H NMR (CDCl3, 300 MHz) δ 822 (d, J=4.2 Hz, 1H), 7.58-7.47 (m, 1H), 6.74-6.63 (m, 2H), 4.54 (d, J=6.0 Hz, 1H), 3.88-3.41 (m, 8H), 3.33-322 (m, 1H), 1.89-1.62 (m, 3H), 1.61 (s, 3H), 1.55 (s, 3H), 0.99-0.88 (m, 6H).

1. customAfter 14 h of reaction at RT
2. customthe solvent was evaporated
3. customto give an oil
4. customPurification by chromatography (SiO2)