Nonclassical Arylative Meyer-Schuster Rearrangement through Ni-Catalyzed Inner-Sphere Acyloxy Migration

Abstract

A Ni(II)-catalyzed unconventional Meyer-Schuster rearrangement (MSR) is paired with cross-coupling through inner-sphere acyloxy migration. Various propargyl acetates react with aryl boronic acids, leading to the formation of a range of alpha-arylated enone derivatives. This transformation is enabled by the use of a P boolean AND N-type phosphinooxazoline (PHOX) ligand, which allows the substrate to coordinate with the square planar Ni(II) center. It initiates arylnickelation of the alkyne moiety followed by intramolecular transposition of the acetate group. This nonclassical approach allows for the addition of electron-rich nucleophiles at the a-position without the need for redox additives. A series of controlled experiments including O-18 isotope labeling studies and computational analysis corroborated the inner-sphere acyloxy migration.