Late-transition-metal-catalyzed Inert C-H Functionalization

In recent years, transition-metal-catalyzed coupling reaction for the formation of C-C, C-X bonds is one of the most effective ways to construct organic molecules. However, it usually needs to prefunctionalize the coupling partners. The strategy of inert C-H functionalization can directly convert C-H bonds to C-C or C-X bonds without prefunctionalization, and thus it is more atom-economical, step-economical and environmentally friendly. The C-H functionalization is of great interest and significance to chemists.In 21st century, the rapid development of chemical industry brings us many benefits, also the negative effects. The disadvantages are not harmonious with the modern civilization. Therefore, it’s the responsibility for us to develop green, efficient and low-energy-consumption chemistry. In this thesis, we mainly focus our attention on the development of late-transition-metal complex (Au, Ru, Ir et al.) catalyzed mild, efficient and green C-H functionalization method for C-C and C-X coupling by thermochemical and photochemical way, as well as the organocatalytic C-H functionalization.The thesis includes the following five aspects.1. In the gold-catalyzed oxidative coupling, it usually requires strong oxidant such as Selectfluor, PhI(OAc)2 or NFSI to complete the catalytic cycle of gold. We have developed a highly efficient gold-catalyzed oxidative C-C coupling of tertiary amines with nitroalkanes, methylketones and cycloketones using air as the benign oxidant. This piece of work is a nice addition to gold chemical society.2. We developed a scalable and efficient gold-catalyzed aerobic oxidative phosphonation of sp3 C-H bonds with various diarylphosphine oxides and dialkyl phosphites using air as a sustainable oxidant under mild reaction conditions. It provides an easy access to a-amino phosphonic compounds in high yields with a broad reaction scope.3. With Ru(pby)32+ as the photocatalyst, we developed a visible-light-promoted aerobic C-H/C-N cleavage cascade to isoxazolidine skeletons from simple tertiary amines and a-ketoesters through a C-H activation-retro-aza-Michael-oxidation-cyclization tandem sequence. The forging of two C-C, one C-O and one N-O bonds, the construction of two new rings and the formation of one quaternary carbon center can be perfectly accomplished in one process under mild reaction conditions. This protocol provides a concise approach to dactylicapnosinine derivatives.4. With fac-Ir(ppy)3 as the photocatalyst, we developed an excellent approach to quaternary oxindoles through a room temperature decarboxylative C-C coupling/radical C-H functionalization cascade by visible-light photoredox catalysis. It possesses the ability to quickly couple to a number of readily available primary, secondary and tertiary aliphatic carboxylic acids bearing different functional groups. This protocol can easily expand the structure diversity of oxindoles.5. We developed an metal-free, Bu4NI cascade reaction that involves the formation of C-N, C-O and C=N bonds in one process via dual sp3 C-H functionalization. This protocol affords a facile methodology for the synthesis of oxazole derivatives in air under mild conditions.