Pd-Catalyzed Conversion of Aryl Chlorides, Trifiates, and Nonaflates to Nitroaromatics

摘要

Aromatic nitro compounds are of great importance to a variety of disciplines. They can be found in an array of Pharmaceuticals, dyes, and materials. Moreover, they are important entities in synthesis and can participate in a range of useful transformations. Most commonly, nitrobenzenes are synthesized via electrophilic aromatic substitution using HNO_3 and a strong acid or with dinitrogen pentoxide. However, these methods suffer from issues of poor regioselectivity and imperfect functional group tolerance. Further, the application of these reactions is particularly problematic for the nitration of heteroaromatics. More recently, Prakash and Olah disclosed a method for the conversion of aryl boronic acids to aryl nitro compounds. This was followed by a report from Saito disclosing a copper catalyst for the transformation of aryl iodides to nitrobenzenes. These processes were important advances in this field and provided nitration protocols complementary to known chemistry; however, the substrate scope of these reactions is limited and does not include heterocycles.