Palladium-Catalyzed Carbonylation Coupling Reactions Of Halogenated Hydrocarbons

The coupling reaction catalyzed by transition metal palladium is one of the effective methods to construct C-C bonds in complex molecules.In the first chapter of this article,taking the palladium-catalyzed cross-coupling reaction as a starting point,the development and current situation of the palladium-catalyzed carbonylation coupling reaction are introduced.First,the palladium-catalyzed carbonylation coupling reaction of halogenated hydrocarbons and unsaturated hydrocarbons is introduced.Then,from the perspective of the sources of different carbonyl reagents such as CO,formic acid and its derivatives,aldehyde compounds,metal carbonyl compounds,chloroform and acid chlorides,the palladium-catalyzed carbonylation reaction is described.After decades of development,the palladium-catalyzed carbonylation reaction provides a direct and effective synthetic method for the preparation of a variety of biologically active carbonyl compounds,and this method of directly constructing carbonyl groups also has the advantages of high efficiency and good atom economy.Since Heck reported the pioneering study of palladium-catalyzed carbonylation,people have been committed to the study of transition metal-catalyzed carbonylation coupling reactions.Correspondingly,in the case of organic compounds containing other functional groups,palladium-catalyzed carbonylation has become an indispensable method for introducing carbonyl groups and realizing polyfunctionalization of related compounds.It is also considered to be one of the most challenging and interesting research fields in organic chemistry.Under mild reaction conditions,the use of glyoxylic acid as a carbonyl source reagent to realize the formylation reaction of aryl halides is a hot issue in organic chemistry research.In the research work in Chapter 2 of this article,we achieved that enabled by organophotoredox/palladium cooperative catalysis,glyoxylic acid monohydrate is successfully used as formyl synthetic equivalent which decarboxylatively couples with aryl halides to synthesize a variety of arene and heteroarene carbaldehydes.The reaction provides a practical method for the preparation of functionalized aryl and heteroaryl aldehydes under mild conditions,and represents a new synthetic application of the increasing repertoire of photoredox/palladium cooperative catalysis.The thiocarbonylation and hydrothiocarbonylation reactions usually require the use of mercaptans and thiophenol compounds with a strong pungent odor,and the participation of CO increases the difficulty of operation and the cost of equipment.In the research work in Chapter 3 of this article,we achieved that oxalic acid monothioester(OAM)for palladium-catalyzed decarboxylative thiocarbonylation and hydrothiocarbonylation.Oxalic acid monothioesters,which are easily available,bench stable,and odor-free solids,as a thioester synthetic equivalent for palladium-catalyzed decarboxylative thiocarbonylation of organohalides and hydrothiocarbonylation of unsaturated carbon carbon bonds at room temperature with high chemo-and regioselectivity.The mild reaction conditions also allow application of this method to the synthesis of cysteine-derived thioesters and allowing chemical modification of cysteinecontaining peptides.Alkyl ketones with large steric hindrance are usually difficult to prepare by traditional carbonylation coupling reaction methods.In the research work in Chapter 4 of this article,we achieved the alkylation of silyl enol ether and enamide with tertiary,secondary,and primary alkyl bromides was achieved using visible-light-induced palladium catalysis applying a dual phosphine ligand system.The reactions effectively deliver ?-alkylated ketones,and ?-alkylated N-acyl ketimine in a stereoselective manner.The ?-alkylated N-acyl ketimine products can be subjected to chiral phosphoric acid-catalyzed asymmetric reduction with Hantzsch ester to deliver chiral ?-arylated N-acyl-protected aliphatic amines in high enantioselectivity up to 99%ee.The N-acetyl ketimine products also reacted with various Grignard reagents to produce N-acetyl ?-tertiary amines in good yields.Through the study of palladium-catalyzed coupling reactions and carbonylation reagents,the synthesis methods of carbonyl compounds have been broadened,the types of palladium-catalyzed carbonylation coupling reactions have been enriched,and the new applications of palladium catalysis in organic synthetic chemistry have been expanded.Of course,the research on palladium catalytic chemistry is still not deep enough,such as the use of excited-state palladium to realize the construction of C-N,C-B and C-Si bonds.These issues will be the direction and goal of our continued research.