Diethyl Ether → (2R)-1-(5-chloro-2-methylphenyl)propan-2-ol

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 4-chloro-2-iodo-1-methylbenzene (5.05 g, 20 mmol) in 100 mL of anhydrous THF was cooled to −100° C. (liquid nitrogen/EtOH) under nitrogen. Then 1.4M solution of sec-BuLi in cyclohexane (15 mL, 21 mmol) was added dropwise at −100° C. to −90° C. The mixture was stirred at −100° C. to −90° C. for 10 min, then a solution of R-(+)-propylene oxide (1.51 g, 1.8 mL, 26 mmol) in 15 mL of THF was added dropwise at −100° C. to −90° C., then the mixture was cooled to −105° C. and a 46.5% solution of BF3 in diethyl ether (4.18 mL, 30 mmol) was added dropwise. The mixture was stirred at −100° C. to −90° C. for 2 h, then the reaction was quenched with 20 mL of sat. aq. NH4Cl at −90° C. The mixture was stirred and warmed to 0° C. overnight. Then 20 mL of water was added and mixture was extracted with EtOAc (2×60 mL), the extract was dried over Na2SO4 and evaporated to give crude oil, which was purified by column (silica gel, EtOAc/hexane 1:9, Rf=0.43 in EtOAc/hexane 3:7) to give (2R)-1-(5-chloro-2-methylphenyl)propan-2-ol (1.39 g, 38%) as pale yellow oil. 1H NMR (300 MHz, CDCl3): δ 7.16 (s, 1H), 7.10 (m, 2H), 4.03 (m, 1H), 2.73 (m, 2H), 2.29 (s, 3H), 1.86 (s, 1H), 1.27 (d, J=6.24 Hz, 3H).

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