Nat. Catalyst.: Professor Lutz Ackermann, University of Gottingen, Germany realizes chelate assisted activation of multifunctional C-C bond catalyzed by manganese

C-H bond activation has become one of the efficient methods to construct molecular structure In contrast, the methods of activating C-C bond by organic metals are rarely reported In recent years, although Murakami, bower, Dong and other research groups have made great progress in this field, these C-C bond Functionalizations are mainly limited to precious and toxic transition metal catalysts, such as rhodium, ruthenium and palladium catalysts, while the conversion of cheap metal catalysts is less In addition, the sensitivity of transition metal catalysts makes it difficult to functionalize the C-C bond in water phase Recently, the research team of Professor Lutz Ackermann at the University of Gottingen in Germany solved the above problems They used cheap manganese catalyst to realize C-C allylation, C-C Allylation and C-C alkylation in water phase Relevant articles were published on NAT Catalyst (DOI: 10.1038/s41929-018-0187-1) (source: Nat Catalyst.) at the beginning of the study, the author investigated the feasibility of manganese catalyzed C-C bond activation with typical 1a and 2A substrates (Table 1) After a lot of conditions selection, the author found that mnbr (CO) 5 was the catalyst, water was the solvent, and the reaction result was the best The control experiments show that manganese catalyst is the key to the reaction It should be noted that the hydroxyl group in substrate 1A or 4 is necessary for the breaking of C-C bond, while ether 5, ketone 6 or acid 7 can not form the target product 3AA (Figure 2) (source: Nat Catalyst.) (source: Nat Catalyst.), after obtaining the optimal reaction conditions, the author investigated the universality of the substrate arene 1 (Fig 3a) A variety of pyrazoles, pyridines and indazoles can react smoothly, and the reaction has good tolerance to bromine, acylamino and hydroxyl groups The multifunctional activation of C-C bond is not limited to decarboxylation in water Under the same reaction conditions, alkyne 9 can realize C-C alkenylation in water phase (Fig 3b) Manganese (I) catalyzes the functionalization of alkyne 9 with excellent enantioselectivity, and only e-isomers are obtained Alkyne 9 also has a wide range of substrates, and the terminal alkyne and internal alkyne 9 substituted by aryl and alkyl can react smoothly Even at low reaction temperature, steroids and even amino acids can react smoothly without racemization of stereocenters (source: Nat Catalyst.) in addition, olefin 11 is also a suitable substrate in the aqueous phase, and the corresponding alkylated aromatics 12 (FIG 4A) can be obtained with excellent chemical and position selectivity In addition, an efficient C-C allylation method has been designed, which provides a convenient way for the synthesis of α, β - unsaturated ester 17 (source: Nat Catalyst.) the author also synthesized 1,2,3-Trisubstituted aromatic hydrocarbons (10,17 and 3) by site selective synthesis, which further highlighted the unique charm of the C-C activation strategy (Fig 5A and 5b) Finally, in order to prove the practicability of the C-C activation strategy, a useful aniline derivative 18 (Fig 5C) was synthesized by removing pyrazole guiding group without trace (source: Nat Catalyst.) then, the author confirmed that C-C fracture is the decisive step of the reaction through detailed mechanism experiments, spectral and kinetic studies Then, based on the study of computational chemistry, the author proposed a reasonable reaction mechanism (Figure 8) Manganese (I) alkoxide a was formed by the decomposition of salt, which laid a foundation for the fracture of C-C bond After that, the intermediate g was formed by migration insertion of a and elimination of β - oxygen Finally, the target product 3 was produced by decarboxylation of the complex g and the catalytic active substance A was produced by proton demetallization (source: Nat Catalyst.) conclusion: Professor Lutz Ackermann's research group reported the method of manganese catalyzed C-C bond activation In terms of C-C allylation, C-C Allylation and C-C alkylation, manganese catalyzed C-C bond functionalization has excellent chemical, regional and site selectivity The functionalization of C-C bond in green nontoxic aqueous phase shows the unique stability of manganese (I) catalysis In addition, the mechanism of chelate assisted C-C bond activation was studied in detail by means of spectroscopy, kinetics and computational chemistry It is worth noting that the activation of C-C bond catalyzed by manganese (I) is faster than the common C-H bond activation reaction, and can control its site selectivity, which further proves the unique potential of manganese catalyzed C-C bond functionalization in sustainable molecular synthesis.