Palladium-Catalyzed Tandem Heck Cyclization/Reduction Aminocarbonylation Reactions To Construct Benzo-Heterocyclic Amide Compounds

Benzo-heterocyclic compounds have attracted the attention of many chemists because of their good biological activity and unique physical and chemical properties.Among them,Benzofuran and indole derivatives are the most basic skeleton units in pharmaceutical chemistry,agricultural chemistry and chemical raw materials,especially in the field of pharmaceutical chemistry has a high application value.In the past few decades,palladium-catalyzed Heck cyclization has become one of the most efficient and convenient methods for the construction of benzo-heterocyclic compounds.At present,palladium-catalyzed Heck cyclization/carbonylation reaction has become one of the hottest topics in the field of synthesis,which can not only insert carbonyl groups into the target compound to extend the carbon chain,but also enrich the compound’s multifunctional.On the other hand,nitro compounds themselves are rich in nitrogen sources,with various varieties and low prices.The application of nitro compounds as nucleophiles in reducing amino carbonylation reactions can avoid the step of pre-reduction to amine and further accelerate the reaction rate.The first part of this thesis describes that after Heck reaction of intramolecular with reasonably designed substrate,subsequent series reactions can be further triggered and benzo-heterocyclic compounds can be obtained.This strategy has been used as a key step in the total synthesis of multiple natural products.There are two types of carbonylation reactions involving nitro compounds:（1）the carbonylation of nitro compounds with activated C-X bonds（X=I,Br,B（OH）₂,H,OTf...）;（2）carbonylation of nitro compounds withπ-conjugated systems（olefins,alkynes,allenes,etc.）.In the second part of this thesis,palladium-catalyzed Heck cyclization/amino carbonylation of o-Allyloxy（amino）iodobenzene with nitro compounds was described,and a series of benzo-heterocyclic amide compounds with medium to good yields were prepared.The reaction conditions are mild and solid molybdenum hexacarbonyl is used as the substitute carbonyl source.Both nitroarenes and nitroalkanes are suitable for the reaction.In addition,two C-C bonds,one C-N bond and one N-H bond are formed through one step reaction.