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

Abstract

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.