Synthesis of naphtho[1,2-b]furan-2-carbaldehydes and naphtho[2,1-b]furan-2-carbaldehydes via electrocatalytic 3,3-rearrangement/cyclization of propargylic aryl ethers under mild conditions

An electrocatalytic 3,3-rearrangement/cyclization approach has been developed for the transformation of aryl-substituted propargylic aryl ethers to naphtho[1,2-b]furan-2-carbaldehyde and naphtho[2,1-b]furan-2-carbaldehyde derivatives. The reaction proceeded efficiently under mild conditions in the absence of metal- and chemical-oxidant, yielding the desired products with good substrate scope and functional group tolerance via a radical pathway. Furthermore, the control experiment revealed that the phenylselenyl-substituted secondary alcohol might be intermediate, and the 18O labeling reaction indicated the oxygen source in the product possibly deriving from water. Significantly, further transformations of the product were conducted to showcase the utility of this electrosynthesis strategy.