Studies On Palladium-Catalyzed Alkynes Cyclization Reactions

The thesis aims at the studies on the palladium-catalyzed alkynes cyclization reactions. It mainly consists of the following five parts.PartⅠ:Summarized the more recent progress in palladium-catalyzed alkynes cyclization reactions.According to the reaction processes,we classified them in three types:1) cyclization viaπ-alkyne complex.2)cyclization via ~2η-alkyne-organopalladium complex.3)cyclization via allenylpalladium complex.In this review,we introduced their applications in the synthesis of carbocyclic and heterocyclic compounds respectively.PartⅡ:Introduced the progress in palladium-catalyzed cyclization reactions of alkynes containing a nucleophilic center in close proximity to the carbon-carbon triple bonds promoted by organopalladium complexes and extended this method to the synthesis of carbocyclic compounds.We have developed an efficient way to the synthesis of 2,3-didistituted indenes via the palladium-catalyzed carboannulation of diethyl 2-(2-(1-alkynyl)phenyl)malonate with organic halides.We proposed this cyclization proceeded via a 2η-alkyne-organopalladium complex.PartⅢ:Introduced the progress in palladium-catalyzed domino cyclization/coupling reactions initiated by intramolecular Heck reactions and their application in the synthesis of cyclic compounds.We have prepared structurally versatile indene and naphthalene derivatives in good-to-high yields by palladium-catalyzed Heck/Suzuki-Miyaura,Heck/Sonogashira and Heck/Heck domino reactions.This transformation leads to the formation of two C-C bonds in a one-pot process and high selectivity is observed for the sequential process.PartⅣ:Introduced the progress in palladium-catalyzed cyclization reactions of propargylic compounds with nucleophiles and extended this reaction to the synthesis of carbocyclic compound.We have developed an efficient method for the synthesis of 2-substituted indenes though the reaction of propargylic carbonates containing a proximate carbon nucliphile with oxygen or nitrogen nucliphiles.This method shows some advantages in terms of its high yields,simple operation,easily availability and diversity of the nucliphiles.PartⅤ:Introduced the progress in palladium-catalyzed tandem C-H activation/ biscyclization reaction and enlarged the scope of this reaction.We firstly reported a novel tandem C-H activation/biscyclization reaction initiated by propargylic compounds with terminal alkynes.This reaction involved a sequence of carboannulation,C-H activation,coupling and C-C bond formation process,and constructed three C-C bonds and two carbocycles in one step.In this reaction,all the C-H bond of benzene,heteroaromatic rings,or simple C-C double bonds can be functionalized.Furthermore,a rational mechanism has been proposed according to the deuterium-labeling experiment.