Research Of Chemo-Selective Hydrogenation Of ?-methylene-?-Keto Carboxylic Acids And Transfer Hydrogenation Of Cyclic N-Sulfonylimines

Transition metal catalyzed hydrogenation and transfer hydrogenation have perfect atom economy and high efficiency,which is not only one of the most important methods for the construction of chiral compounds,but also an significant direction for achieving green catalytic synthesis and sustainable development.In recent years,it has been widely studied and applied in academia and industry.Carboxylic acids and amines are the most commonly used chemical intermediates and widely used in the production of pharmaceutical active ingredients,fine chemicals,agrochemicals,polymers,dyes,pigments,emulsifiers and plasticizers.However,these important compounds are not readily available.Although it is enable to realize various carboxylic acid and amine compounds depending on the transition metal catalytic hydrogenation,the existing metal catalyst has various disadvantages and resources are limited,which is difficult to achieve sustainability.Therefore,it is of great significance to develop novel catalysts with high activity and enantioselectivity to prepare carboxylic acids and amine compounds.?-methylene-?-ketocarboxylic acid is a special unsaturated carboxylic acid,which can derive various valuable chiral?-keto acid compounds by asymmetric hydrogenation,and is conveniently used for the synthesis of many important drugs and natural products,such as sacubitril?for the treatment of heart failure?and cryptophycin?an effective antimitotic antitumor agent?and the natural product geodiamolide A-F.Our group successfully achieved high-efficiency selective hydrogenation of?-methylene-?-ketocarboxylic acid under palladium/zinc Co-catalyzed system.Under the same reaction conditions,This methodology offers a divergent synthesis of?-methyl-?-keto carboxylic acids,?-methylcarboxylic acids,and lactones starting from?-methylene-?-keto carboxylic acids via tuning the ligand the selective hydrogenation avoiding the use of high pressure of hydrogen in good to excellent yield.Secondly,our research group realized the transfer hydrogenation of a cyclic sulfonimide with visible light catalysis using water as a hydrogen source.We used fac-Ir?ppy?₃ as a photosensitizer and diphenyldisulfide as a hydrogen transfer catalyst?HAT?.Under the excitation of 30w visible blue light,various substituted sulfonamides were obtained by transfer hydrogenation.At the same time,we also obtained deuterated sulfonamide compounds with a deuteration rate of 97%when we changed water to deuterium water.We proposed a reasonable reaction mechanism through control experiments and fluorescence experiments.Finally,based on the C-H activation reaction of benzonorbornene compounds,We have successfully relized the Rh?III?-Catalyzed Ring-Opening Addition of Cyclic N-Sulfonyl ketimines to azabenzonorbornadienes via C-H Bond activation.After optimizing the reaction conditions,a derivative of a sulfonyl dihydronaphthalene structure having different substituents can be obtained in a high yield with a low catalytic loading.