Benzoic Acid → (trans)-Benzyl 4-(benzoyloxy)-3-fluoropiperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

Non-racemic (cis)-benzyl 3-fluoro-4-hydroxypiperidine-1-carboxylate (Peak 1 of Example 94, Step 3D; 0.306 g, 1.21 mmol) was treated with triphenylphosphine (0.475 g, 1.81 mmol) and benzoic acid (0.221 g, 1.81 mmol) and the solids were dissolved in THF (5 mL), then cooled to 0° C. The solution was treated dropwise with diisopropyl azodicarboxylate (0.357 mL, 1.81 mmol) dissolved in THF (1 mL). The solution was warmed to ambient temperature with a bath and stirred for 7 days, then concentrated in vacuo. The residue was dissolved in CH2Cl2 and washed with saturated NH4Cl, water, 50% saturated NaHCO3, dried over Na2SO4 and concentrated in vacuo to a colorless oil. The oil was chromatographed on SiO2 eluting with 1:12 acetone/hexanes. The desired fraction was isolated to provide the desired product as a colorless oil (385 mg).

Provenance & Evidence