A modular approach has been developed for an efficient synthesis of an aminal group containing a new tetracyclic framework. The strategy has been devised based on selective hydrogen-bond-guided aza-Michael addition of heteroaromatic amines to cyclohexadienone-aldehydes. The reaction is highly atom economic and practical and involves stereoselective construction of four new C–N bonds and four rings
The cascade difunctionalization of α,β-unsaturated carbonyls by nucleophilic halogenation followed by enolate trapping with other electrophiles is highly challenging in synthetic organic chemistry. Herein, we report a chemo- and diastereoselective cascade annulation of enone-tethered cyclohexadienones by using an unconventional combined Lewisacidcatalyzed halogenation reaction in the presence of