Synthesis of N-substituted quaternary carbon centers through KOt-Bu-catalyzed aza-Michael addition of pyrazoles to cyclic enones?

Organic & Biomolecular Chemistry Pub Date: 2022-10-11 DOI: 10.1039/D2OB01634F

Abstract

This study reports an efficient and mild method for the synthesis of cyclic β-amino ketones containing N-substituted quaternary carbon centers via the KOt-Bu-catalyzed aza-Michael addition reaction of pyrazoles to β-substituted cyclic α,β-enones. The amination was promoted by KOt-Bu (3 mol%) at ambient temperature and a wide range of new and versatile β-pyrazolyl ketones were obtained in good yields. Furthermore, the KOt-Bu-catalyzed one-pot diamination of a cyclic dienone with pyrazoles via an aza-1,6-conjugate addition followed by an aza-1,4-conjugate addition was also explored.

Graphical abstract: Synthesis of N-substituted quaternary carbon centers through KOt-Bu-catalyzed aza-Michael addition of pyrazoles to cyclic enones
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