Novel Sulfinamide-Based Chiral Ligand Promoted Chiral Diarylmethanol Preparation via exo-Directed Asymmetric C–H Alkynylation under Mild Conditions

Abstract

Desymmetrization of diarylmethanols has been achieved by means of exo-directed Pd(II)-catalyzed C–H alkynylation under mild conditions (30 °C). We herein designed a class of chiral N-sulfinyl anthranilic acid (CSAA) ligands with chiral information only at the N-protecting group, which were found crucial for challenging stereocontrol within a conformationally flexible exo-chelated six-membered palladacycle. An array of valuable chiral diarylmethanols were obtained in high yield, good enantioselectivity, and broad functional group tolerance. Gram-scale synthesis was readily carried out and a diverse range of transformations were implemented with high retention of configuration, highlighting the synthetic utility of this method. Preliminary mechanistic studies indicated that CSAAs adopted an N,O-chelation mode, and the chiral induction proceeded through direct interaction between the N-tert-butanesulfinamide motif with the substrate.