Rearrangement strategies for aryl-heteroatom bond formation

A major interest in synthetic research is the controlled introduction and elaboration of new carbon-heteroatom bonds for the synthesis of arom. and heteroarom. products. Recently, C-H functionalization strategies have provided important contributions to the available methods. Although efficient and practical, the majority of these processes rely on activation with transition metals. The development of a metal-free methodol. to activate arom. rings would significantly augment the available methods and provide a valuable synthetic alternative. Within this talk we will present a versatile rearrangement strategy to access new aryl-heteroatom bonds through a formal metal-free C-H functionalization. The N-aryl hydroxylamine substrates for the rearrangement process (1) can easily be accessed from aryl halides via palladium and copper catalyzed coupling or from nitroarenes through a one-pot redn./protection sequence. Products accessed through this technol. provide fundamental building blocks for the prepn. of a variety of pharmacol. important heterocyclic scaffolds.