In recent years, electrocatalysis has rapidly established its dominance in organic synthesis due to its high efficiency and low pollution. However, without methods developed to control regiochemistry and stereochemistry, control of selectivity proved difficult in this field.
Recently, the research team led by Professor GUO Chang from the University of Science and Technology of China (USTC) has succeeded in realizing the asymmetric electrochemical radical functionalization of alkenes and allylation. Relevant achievements were reported in Science Advances and Angew. Chem. International Ed.
The team first activated the nucleophile with a stereoselective Lewis-Nickle acid complex to form a key radical intermediate via oxidation at the anode.
The intermediate was added to various alkenes to form new radicals that were eventually converted to alkene difunctionalization (Path1) or alkenylation (Path2) products by further oxidation and addition (or elimination). Product analysis showed high asymmetric selectivity thanks to the single electron transfer (SET) process and the nickel catalyst.
The researchers conducted extensive experiments on the function and necessity of each reaction component to better understand the mechanism of the asymmetric electrolytic reaction. They found that the electrode potentials of nickel-mediated alkene oxidation are significantly lower than those of direct oxidation.
Furthermore, using similar methods, the team developed an electrocatalytic asymmetric allylation in which the intermediate was an electron-deficient α-ketone radical.
“We believe that in the near future, performing enantioselective electrochemical transformations will improve the scope of electrosynthesis and pave the way to explore new chemical spaces and develop solutions to challenging synthetic problems,” the paper says.
Given the essential role of synthesis in many areas, the research is undoubtedly a deep insight into the potential of electrosynthesis.
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