Truce–Smiles rearrangement of substituted phenyl ethers

Abstract

The requirement of aryl ring activation by strong-electron withdrawing substituents in substrates for the intramolecular nucleophilic aromatic substitution reaction known as the Truce–Smiles rearrangement was examined. Preliminary mechanistic experiments support the S_NAr mechanism, including ¹H and ¹³C NMR spectra of a Meisenheimer intermediate formed in situ. The rearrangement was generally observed to be successful for substrates with strong electron withdrawing substituents, such as nitro-, cyano-, and benzoyl- functional groups, but also for those with multiple, weakly electron withdrawing substituents, such as chloro- and bromo-functional groups. These results lend further clarification to the effect of aryl substituents in this type of S_NAr reaction. Additionally, the survey revealed several tandem cyclization and/or elimination reactions accessed by certain substrates.