Catalytic Asymmetric Cascade Cyclization for Constructing Three Contiguous Stereocenters in Pyrrolobenzodiazepine-Based Cyclopentanones.

A chiral Brønsted acid catalyzed highly enantio- and diastereoselective cascade cyclization has been developed to streamline the synthesis of valuable multifunctionalized enantioenriched cyclopenta[ f]pyrrolo[1,2- d][1,4]diazepinones bearing three contiguous stereocenters in high yields with excellent control of stereochemistry from a wide range of both readily available 2-furylcarbinols and (1 H-pyrrol-1-yl)anilines, which represents the first asymmetric intramolecular conjugate addition of α,β-unsaturated cycloketones with inert N-substituted pyrroles as well as the first enantioselective aza-piancatelli rearrangement/Friedel-Crafts alkylation cascade reaction.