Studies On Palladium-Catalyzed Alkynes Cyclization And Enyne Cycloisomerization

The present thesis aims at describing the fundamental studies on palladium-catalyzed carboannulation and enyne cycloisomerization. It mainly consists of the following three parts:Chapter1. Palladium-catalyzed alkynes cyclization and enyne cycloisomerization reactionsSummarized the more recent progress in palladium-catalyzed alkynes cyclization and enyne cycloisomerization reactions. Introduced the character of palladium compounds, complexes and the mechanism of palladium-catalyzed.Chapter2. Palladium-catalyzed [1,5]-Sigmatropic Hydrogen Shift of Propargylic Esters toward Substituent NaphthylaminesPalladium-catalyzed carboannulation of propargylic ester has been applied in the cyclization reactions and various naphthylamines have been synthesized. The reaction might include the [1,5]-sigmatropic hydrogen shift and6-π cyclization processes. After optimization of reaction conditions, we studied the scope of this reaction and the effect of different protective groups. The deuterium-labeling experiments were also carried out to reveal the mechanism.Chapter3. Palladium-Catalyzed Divergent Reactions of1,6-Enyne Carbonates: Synthesis of Vinylidenepyridines and VinylidenepyrrolidinesPalladium-catalyzed carboannulation of1,6-enyne carbonates has been applied in the organic synthesis and various3-vinylidene-1-tosylpyridines and3-vinylidene-1-tosylpyrrolidines have been synthesized. The reaction might include allenylpalladium intermediate, attacked by olefin nucleophile and β-hydrogen elimination processes. We controled the conditions of the recation to afford3-vinylidene-1-tosylpyridines and3-vinylidene-1-tosylpyrrolidines. After optimization of reaction conditions, we studied the scope of this reaction. we propose the plausible mechanisms for palladium-catalyzed intramolecular cyclization reactions...