Chiral Phosphoric Acid-Catalyzed Asymmetric Doyle Indolization: Enantiodivergent Access to Indolizinylindoles

We present here a chiral phosphoric acid-catalyzed asymmetric Doyle indolization enabling efficient construction of axially chiral indolizinylindoles with stable C-N stereogenic axes. Importantly, this intriguing cascade cyclization realized the highly enantioselective synthesis of axially chiral o-quarteraryl skeletons containing two contiguous stereogenic axes in good to high yields and excellent stereoselectivities. Furthermore, an atropo-divergent synthesis was achieved via switching the 3,3'-substituents of the CPA catalyst. The potential synthetic utility of this method was further illustrated by easy scale-up and diverse late-stage functionalizations through reduction or oxidation.