Axially Chiral 2-Hydroxybiaryls by Palladium-Catalyzed Enantioselective C–H Activation

Abstract

This article describes the discovery and development of a palladium-catalyzed asymmetric C–H olefination of 2-hydroxybiaryls. The strategy allows a direct assembly of optically active, axially chiral 2-substituted-2′-hydroxybiaryls from readily available precursors and demonstrates that the native hydroxy unit of the substrates can work as an efficient directing group for the C–H activation. This represents a substantial advantage over other approaches that require the preinstallation of metal coordinating units. The simplicity of the approach and versatility of the products allow a practical and efficient synthesis of a broad variety of optically active binaphthyl derivatives.

Developing Biarylhemiboronic Esters for Biaryl Atropisomer Synthesis via Dynamic Kinetic Atroposelective Suzuki–Miyaura Cross-Coupling

“…Although simple alkyl halides were not tolerated, the reaction with benzyl bromide could proceed smoothly to give the coupling product in a moderate yield with 92% ee ( 3az ). The chiral 2′-hydroxylbiaryl products obtained here are not easily accessible by existing methods …”