Transition Metal-catalyzed C-C And C-N Coupling Of Arenes Via C-H Functionalization Assisted By Oxygen-containing Directing Groups

Over the past decade,transition-metal-catalyzed C-H bond activation has been considered to be one of the effective methods for constructing C-C and C-X?X=heteroatoms?bonds.Especially,site selectivity can be achieved by employing directing groups?DGs?to aromatic substrates.The most common DGs are usually nitrogen-containing groups with good coordination ability,including nitrogen-containing heterocycles,azo,aliphatic amines,and iminoether ethers.However,some other oxygen-containing DGs such as carbonyl,carboxyl,carboxylic ester group,hydroxyl,etc.are less developed.The resulting metallacycles are less thermodynamically stable due to the weak coordination between oxygen atom and transition metal.Consequently,these transformations continue to be scare though they are widely present in many natural products or drug molecules.Therefore,the study of C-H functionalization assisted by oxygen-containing DGs is valuable.This thesis mainly focused on the coupling reactions of aryl substrates with diazo compounds,alkynyl propyl esters and amino reagents,and a series of C-C and C-N bonds are successfully constructed.The following results have been achieved:1.Ruthenium???-and rhodium???-catalyzed chemodivergent couplings of ketene dithioacetals and?-diazo ketones via C-H activationChemodivergent coupling of?-acylketene dithioacetals with diazo compounds has been realized under catalyst control.The Ru?II?-catalyzed C-H activation occurred at the olefinic position,and 1:2 coupling with?-diazoketoesters leads to furfurylation.In contrast,the Rh?III?-catalyzed C-H functionalization occurred at both the olefinic and the ortho C?aryl?-H positions,and[4+2]annulation afforded naphthalenones.The tunable selectivity of C-H activation may find applications in the development of new catalytic systems.2.Ag???-catalyzed nucleophilic addition and friedel-crafts alkylation between?-oxoketene dithioacetals and propargyl carbonatesSilver???-catalyzed coupling of?-oxoketene dithioacetals and tertiary propargylic carbonates has been realized and a series of multi-substituted indenes have been constructed in moderate to good yields.Mechanism studies show that the reaction mainly proceeded through intermolecular nucleophilic addition and intramolecular Friedel-Crafts alkylation.The reaction proceeded under operationally simple conditions with broad substrate scope.In addition,pregnenolone acetate derivative has been synthesized under standard conditions.3.Rhodium???-catalyzed amination and annulation of arenes with anthranils:C-H activation assisted by weakly coordinating amides[Cp*Rh?MeCN?₃]?SbF₆?₂ catalyzed C-H amination of benzoylpyrrolidines and N-substituted isoquinolones with anthranils has been realized under assistance of weakly coordinating tertiary amide,leading to a bifunctionalized amination product which can further cyclize to acridine under in situ or ex situ conditions.This selectivity was under substrate control.What's more,the reaction proceeded with good regional selectivity and functional group compatibility.4.Copper???-catalyzed amination of phenylboronic acids with benzofurazan 1-oxidesCuCl/Phen-catalyzed C-H amination of arylboronic acid with benzofurazan 1-oxide has been achieved,leading to a bifunctionalized aminonitrobenzene with high efficiency.The maximum yield can up to 99%.The reaction occurred under mild and redox-neutral conditions with broad substrate scope and good functional group compatibility.In addition,the coupled products can transformed to other heterocyclic compounds by further derivative reactions.