No 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 SNAr mechanism, including (1)H and (13)C 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 SNAr reaction. Additionally, the survey revealed several tandem cyclization and/or elimination reactions accessed by certain substrates.

Truce-Smiles Rearrangement of Substituted Phenyl Ethers. -The substrate scope of the title reaction with regard to the electronic and steric properties of the aryl substitution pattern is thoroughly evaluated. Thus, the reaction tolerates strongly electron-withdrawing substituents such as nitro-, cyano-and phenylcarbonyl groups as well as di-and trisubstituted chloro-and bromo-substitution patterns, but no fluoroor iodine-substituents. Depending on the substituents' position on the aryl ring yields range from low to excellent, and further tandem cyclization and/or elimination processes may inevitably take place. -(KOSOWAN, J. R.; W'GIORGIS, Z.; GREWAL, R.; WOOD*, T. E.; Org. Biomol. Chem. 13 (2015) 24, 6754-6765, http://dx.doi.org/10.1039/C5OB00812C ; Dep. Chem., Univ. Winnipeg, Winnipeg, Manitoba R3B 2E9, Can.; Eng.) -F. Schill 42-053