Boron trifluoride etherate → (2S)-3-chloro-1-(2,3-diphenylmethylenedioxyphenyl)-2-propanol

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

n-Butyl lithium (2.3 mL of a 9.5M solution in hexane, 22 mmol) was added dropwise to a solution of 5.47 g of diphenylmethylenedioxybenzene (from step 1) in 75 mL of THF at 0° C. After 5 hr the solution was cooled to -78° C., and a solution of 1.85 g (20 mmol) of (S)-(+)-epichlorohydrin (Aldrich Chemical Co.) in 10 mL of THF was added. Boron trifluoride etherate (2.4 mL, 20 mmol) was then added dropwise, and the reaction was stirred for 1.5 hr. The reaction was quenched by addition of 50 mL of saturated NaHCO3, and the mixture was warmed to ambient temperature and partitioned between 100 mL of ether and 100 mL of water. The aqueous phase was extracted with ether (2×40 mL), and the ether extracts were combined and washed with brine, dried over MgSO4 and concentrated in vacuo to give a brown oil, which was purified by flash chromatography over silica gel, eluting with 15% ethyl acetate in hexane, to afford after removal of the solvent 4.23 g of the title compound as a light yellow oil (58% yield). MS (DCI/NH3) M/Z: 367 (M+H)+, 384 (M+NH4)+. 1H NMR (CDCl3, 300 MHz) δ: 2.3 (d, 1H), 2.9-3.0 (m, 2H), 3.5 (dd, 1H), 3.6 (dd, 1H), 4.1-4.23 (m, 1H), 6.65-6.85 (m, 3H), 7.37 (m, 6H), 7.55 (m, 4H).

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