Hydrogen-Bond-Guided Reaction of Cyclohexadienone-aldehydes with Amines: Synthesis of an Aminal Group Containing a Fused Tetracyclic Framework.

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 synthetic utility of the tetracyclic product was explored. The role of a H-bond was explained with the help of experimental and density functional theory (DFT) computation studies.