1,8-Diazabicyclo(5.4.0)undec-7-ene → tert-Butyl 3,6-dihydropyridine-1(2H)-carboxylate

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Reaction Steps

A solution of tert-butyl 4-[(methylsulfonyl)oxy]piperidine-1-carboxylate (312 g, 1.12 mol) and DBU (400 g, 2.24 mol) in THF (4.5 L) was heated to reflux overnight. The mixture was poured into ice-water (2 L) and then extracted with EtOAc (2 L). The combined organic phase was washed with 1 M HCl solution (4 L×2), aq. NaHCO3 (4 L), and dried over anhydrous sodium sulfate. The residue was concentrated to afford tert-butyl 3,6-dihydropyridine-1(2H)-carboxylate, which was used in the next step without further purification.

Provenance & Evidence