Design of Chiral Antimony Catalyst for Ring-Opening Reaction of Epoxides with Anilines

Abstract

Pnictogen-bonding catalysis has emerged as a promising tool for noncovalent transformations; however, its application in asymmetric catalysis remains in its infancy, largely due to the scarcity of efficient chiral catalysts and activating modes. Herein, we report a new class of chiral antimony catalysts featuring strong σ-hole strength and a tunable chiral environment, which are readily assembled from tetraarylantimony bromides bearing electron-withdrawing substituents and chiral silver phosphates. These catalysts enable the asymmetric ring-opening of epoxides with anilines, affording a range of chiral β-amino alcohols in high yields and with excellent enantioselectivities. Mechanistic studies, including control experiments, NMR spectroscopy, and DFT calculations, reveal that this enhanced σ-hole character is crucial for the electrophilic activation of epoxides. Collectively, this work establishes chiral antimony catalysts as a powerful and general platform for asymmetric pnictogen-bonding catalysis.