Radical Rearrangement Reaction of Propargyl Ethers to α,β-Unsaturated Aldehydes via Photoredox and Ni Catalysis

Aryl migration, especially 1,4-aryl migration, is one of the most important reactions in radical rearrangement. Over the past decades, 1,4-aryl migration by the addition of a radical to alkynes has become a simple and efficient method in the difunctionalization reactions of alkynes. Radical-based 1,4-aryl migration of aryl alkynoates has been well-explored; however, the 1,4-aryl migration of aryl propynyl ethers is rarely studied. Herein, we first described radical 1,4-aryl migration of propargyl ether to valuable α,β-unsaturated aldehydes via photoredox and Ni catalysis. This method features redox-neutral conditions, readily available starting materials, broad substrate scope, good functional group compatibility, and diverse transformations. Mechanistic studies suggest that this reaction proceeds through a radical-involved pathway.