tert-Butyl 4-oxopiperidine-1-carboxylate → Tert-butyl 4-(3-bromobenzylidene)piperidine-1-carboxylate

Participants

Reaction Steps

To diethyl[(3-bromophenyl)methyl]phosphonate (100 g, 326 mmol) in a 2 L 3-neck flask with mechanical stirrer was added tetrahydrofuran (THF) (700 mL) followed by 1,1-dimethylethyl 4-oxo-1-piperidinecarboxylate (71.4 g, 358 mmol) and potassium tert-butoxide (38.4 g, 342 mmol), portion-wise with ice-bath cooling to keep the temperature between 20° C. and 25° C. The mixture became more orange and was then stirred at room temperature under nitrogen. Some material was present as a suspension and it was slightly more viscous. Another 3.8 gm (0.1 eq) of potassium tert-butoxide was added. After 1.25 h the mixture had practically gelled and an extra 150 mL of THF were added.

Provenance & Evidence