Tert-butyl 3-oxopiperidine-1-carboxylate → Tert-butyl 3-[1-(3-fluorophenyl)methylidene]piperidine-1-carboxylate

Participants

Reaction Steps

(3-Fluorobenzyltriphenylphosphonium bromide (Intermediate 228, 5.3 g) was added in portions to a solution of sodium tert-butoxide (1.06 g) in anhydrous THF (20 mL) at room temperature and the mixture was stirred for 30 minutes. A solution of tert-butyl 3-oxopiperidine-1-carboxylate (2 g) in anhydrous THF (10 mL) was added dropwise at room temperature and the mixture was stirred for 24 hours. The mixture was diluted with water (100 mL) and extracted with ether (100 mL), washed with brine, dried (Na2SO4) and filtered. The filtrate was concentrated in vacuo and the residue was purified by chromatography on silica eluting with a mixture of ethyl acetate and cyclohexxane with a gradient of 0-20% to give tert-butyl 3-[1-(3-fluorophenyl)-methylidene]piperidine-1-carboxylate (1.42 g).

Provenance & Evidence