A Ru-catalyzed direct CH activation/meta-bromination of arenes bearing pyridyl, pyrimidyl, and pyrazolyl directing groups has been developed. A series of bromo aryl pyridines and pyrimidines have been synthesized, and further coupling reactions have also been demonstrated for a number of representative functionalized arenes. Preliminary mechanistic studies have revealed that this reaction may proceed through radical-mediated bromination when NBS is utilized as the bromine source. This type of transformation has opened up a new direction for the radical non-ipso functionalization of metal with regard to future CH activation development that would allow the remote functionalization of aromatic systems.

An improved procedure is described for the preparation of pyranoflavylium cations from the reaction of 5,7-dihydroxy-4-methylflavylium cation with aromatic aldehydes. Modifications of the procedure of Chassaing et al. ( Tetrahedron Lett . 2008 , 49 , 6999–7004; Tetrahedron 2015 , 71 , 3066–3078) circumvent the reported restriction to electron-rich benzaldehydes and provide access to a wide variety of substituted pyranoflavylium cations, including those with electron-withdrawing substituents or an attached heterocyclic or polycyclic aromatic ring. This opens the way for studies of substituent and structural effects on the ground and excited states of these pyranoanthocyanin analogues, the behavior of which should mirror fundamental aspects of the chemistry and photophysics of the pyranoanthocyanin chromophores present in mature red wines.

We report our latest discovery of norbornene derivative modulated highly mono-selective ortho-C-H activation alkylation reactions on arenes bearing simple mono-dentate coordinating groups. The reaction features the use of readily available benzamides and alkyl halides. During the study, we prepared 30 mono-alkylated aryl amides in good yields with good mono-selectivity. We have also demonstrated that structurally rigid alkenes such as norbornene and its derivatives are a good class of ligand and could be used for future direct C-H functionalizations. The utilization of norbornene type ligands for assistance in C-H activation processes has opened a new window for future molecular design using direct C-H functionalization strategies.