Enantioselective Synthesis of Atropisomeric 3,3′-Biindoles via Three-Component de Novo Indolization

Abstract The catalytic atroposelective synthesis of 3,3′-biindoles remains a formidable challenge due to the inherent configurational lability of the [5–5] heterobiaryl system. Herein, we report a three-component de novo indolization from simple α-keto aldehydes, 2-substituted indoles, and 2-naphthylamines, enabled by a relay catalysis of Ca(NTf2)2 and chiral phosphoric acid. This cascade constructs both the biindole framework and the chiral axis in one operation, tolerating a broad range of substituents to afford diverse products with good yields and excellent enantioselectivities.