Asymmetric Deoxygenative Difunctionalization of 1,2‐Dicarbonyl Compounds Enabled by Phosphinite and Chiral Salen‐Molybdenum Catalyst Synergy

Abstract

ABSTRACT The 2‐aryl benzofuran‐3‐ones serve as pivotal scaffolds in natural products and bioactive molecules, yet their synthesis and subsequent asymmetric functionalization are hindered by multi‐step protocols and the lability of their derivatives lacking electron‐rich substituents on the aromatic ring of benzofuran‐3‐one core. Herein, we report a phosphinite‐mediated, Mo‐catalyzed intermolecular asymmetric deoxygenative coupling reaction between 1,2‐dicarbonyl compounds and 3‐(methoxymethyl)indoles, thus providing a series of chiral 2‐aryl benzofuran‐3‐ones with a chiral quaternary carbon center with generally good yields and enantioselectivities. Mechanistic studies reveal that phosphinite and the Mo‐complex synergistically promote the in situ generation of key intermediates, while the formally tetravalent mononuclear Mo‐complex serves as the key species governing the enantioselectivity of the reaction. This work expands the application of chiral salen‐Mo catalysts in asymmetric catalysis, offering an efficient route to valuable chiral benzofuranone derivatives.