Copper-Catalyzed 1,3-Propargyl Shift: Development of an Anionic Rearrangement of ortho -Metalated Aryl Propargyl Ethers

Abstract A novel anionic [1,3]-rearrangement of ortho-metalated aryl propargyl ethers was developed. A catalytic amount of copper(I) salt efficiently promotes the 1,3-shift of a propargyl group from an oxygen atom to a carbon atom in an aryl magnesium species, affording phenol derivatives having a propargyl group at the ortho position, which are otherwise difficult to synthesize. The [1,3]-rearrangement proceeds in a stereoretentive manner, thus enabling chirality transfer for asymmetric syntheses of enantio-enriched propargyl compounds. DFT calculations were conducted to elucidate the mechanism of the 1,3-propargyl shift.