Asymmetric Dearomative Cascade Multiple Functionalizations of Activated <i>N</i>-Alkylpyridinium and <i>N</i>-Alkylquinolinium Salts

Abstract

An enantioselective cascade reaction of <i>N</i>-alkylpyridinium and -quinolinium salts with <i>o</i>-hydroxybenzylideneacetones to access fused polyheterocycles through cross dienamine-mediated addition followed by trapping of the dearomatized enamine-type intermediates and aminal formation has been developed. A cascade assembly of <i>N</i>-benzyl-4-methylpyridinium salt and cyclic 2,4-dienones is further disclosed to give bridged frameworks via repetitive dearomatization and aromatization activation.