Synthesis of <i>N</i>-substituted quaternary carbon centers through KO<i>t</i>-Bu-catalyzed aza-Michael addition of pyrazoles to cyclic enones.

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