Palladium-Catalyzed Regioselectivity Of Allenamine Hydrocarbon Research

In recent decades,hydrocarbon reaction has attracted extensive attention of chemical researchers because it can synthesize molecules with complex structure.Among them,palladium catalyzed hydrocarbon reaction has become a simple and efficient technology for the synthesis of natural products and important drug sequences.Allenamine derivatives are structures containing two carbon-carbon double bonds.They can be used as active molecular frameworks for the synthesis of enamine,pyrrole,piperidine,pyridine and other complex functional molecules.How to efficiently realize the regioselective functionalization of allenamine derivatives has always been the focus of our research group.This dissertation focuses on the palladium-catalyzed regioselective hydrogenation of allenamines,and successfully realized two types of reactions:1)Ligand-mediated palladium-catalyzed regioselective aromatic hydrogenation of arylboronic acids and allenamines at the distal double bond Reaction;2)Pd（Ⅱ）-catalyzed intramolecular Metallo-ene cyclization of allenamines.Palladium-catalyzed regioselective aromatic hydrogenation of allenamine derivatives with arylboronic acids via ligand regulation.The reaction system has mild conditions,good substrate universality,and obtains aromatic hydrogenated products with good separation yield and excellent regioselectivity.When the less steric hindrance ligand CH₃CN is used,which could induce E and anti-Markovnikov selectivity;When the sterically hindered bidentate phosphine ligand Dppf/Xantphos is used,inducing excellent E selectivity and anti-Markovnikov selectivity.After a series of mechanism exploration experiments,the mechanism is divided into the following steps:Start reaction（transmetallic exchange）,coordination catalysis,and proton dissociation.After realizing the intermolecular regioselectivity of allenamines,we tried to realize the palladium-catalyzed intramolecular Ene cyclization of allenamines through reactions such as carbon-hydrogen bond activation and hydrogen transfer.Design and synthesis of allenamine derivative raw materials with different substituents,and the optimal conditions,substrate tolerance and reaction mechanism of their hydrocarbon hydrogenation were discussed.At the same time,the construction of new carbon-carbon bonds was also realized has a high degree of C₂ regioselectivity.