Water → 1-tert-Butoxy-3-fluoropropan-2-ol

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A 1.5 L 4-necked sulfonation flask equipped with magnetic stirring bar, reflux condenser, thermometer and an argon in/outlet, was charged with 333.3 mL triethylene glycol, 235.2 g (3.012 mol) finely ground potassium hydrogendifluoride and 200 g (1.536 mol) 2-tert-butoxymethyl-oxirane. The suspension was heated under stirring at an internal temperature of 130° C. for 7.5 h. The mixture was allowed to cool to RT over night, treated with 670 mL water and 350 mL tert-butyl methyl ether, the phases were separated and the aqueous phase was extracted with 350 ml tert-butyl methyl ether. The combined organic phases were washed with 350 mL brine, dried over sodium sulfate, filtered and evaporated. The brown oily residue (286 g) was distilled to provide 141 g (61%) 1-tert-butoxy-3-fluoro-propan-2-ol as colorless liquid, b.p. 80-93° C./70-40 mbar. GC composition: 1.1% 2-tert-butoxymethyl-oxirane, 95.1% 1-tert-butoxy-3-fluoro-propan-2-ol and 3.8% of 3-tert-butoxy-2-fluoro-propan-1-ol. 1H-NMR (CDCl3, 300 MHz): 4.45 (dxm, JH,F=46, —CH2—F); 3.93 (m, br, H—C(2); 3.45 (m, —CH2—O); 2.55 (d, br, J=6, OH); 1.20 (s, C(CH3)3).

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