Access to 2,5-disubstituted furans through a Passerini-Smiles/furyl rearrangement pathway

A one-pot tandem route to functionalized 2,5-disubstituted furans possessing 4-hydroxy-3-nitrophenyl substituents has been achieved through a standard Passerini-Smiles reaction, followed by an unexpected furyl cation-driven skeletal rearrangement. Substitution of the 2-furaldehyde or 2-nitrophenol component determines whether a standard Passerini-Smiles reaction (PS) is followed by rearrangement to produce a rearranged PS-R product. This rearrangement has been confirmed through isolation of the PS product, followed by microwave irradiation to obtain conversion to the PS-R product.

Automated summary

A one-pot tandem route to functionalized 2,5-disubstituted furans has been developed, with the unexpected discovery of a furyl cation-driven skeletal rearrangement. The choice of 2-furaldehyde or 2-nitrophenol component determines whether the standard Passerini-Smiles reaction is followed by rearrangement to produce a rearranged PS-R product. The rearrangement has been confirmed through isolation of the PS product and subsequent conversion to the PS-R product via microwave irradiation.