Palladium-Catalyzed Substitution Reactions Of Allylic Amines Or Allylic Alcohols

Palladium-catalyzed allylic substitution reaction is widely employed in organic synthesis and total synthesis of natural products. It has been deeply studied for decades since it was discovered by J. Tsuji in1965. Research on the palladium-catalyzed allylic substitution reaction is involved in the following aspects: catalysts-ligands system, allylic electrophiles system, nucleophiles system and the asymmetric synthesis. In this dissertation, we focused on1) palladium-catalyzed allylation-olfenation reactions of stabilized phosphonium ylides with primary allylic amines which were the novel electrophilic reagents;2) palladium-catalyzed stereospecific substitution reactions of enantioenriched allylic alcohols with sodium sulfinates.This dissertation includes three chapters.Chapter1:Progress in Palladium-catalyzed allylic substitution reactionsThis section began with analyzing the mechanism of palladium-catalyzed allylic substitution reaction. It was found that one key point for the reaction is the generation of π-allyl palladium intermediates. It was also known that different type of electrophilies would have a significant impact on this process. So the reaction backgrounds on different type of allylic electrophiles, such as allylic halides, allylic sulfones, allylic ethers, allylic esters, allylic alcohols and allylic N-containing compounds are summarized in this chapter. Especially, the background on allylic alcohols and allylic N-containing compounds are emphasized to give us the hint to deveolop new allylic electrophiles, the primary allylic amines as electrophiles. In the aspect of asymmetric synthesis by palladium-catalyzed allylic substitution reaction, we reviewed three models, including asymmetric catalysis, kinetic resolution and chirality transfer. Among the models, chirality transfer mechamism is introduced in detail to rationalize our study on the reaction of allylic alcohols with sodium sulfinates.Chapter2:Palladium-Catalyzed Allylation-Olfenation Reaction of Stabilized Phosphonium Ylides with Primary Allylic AminesIn our studies, a range of stabilized phosphonium ylides were allylated by primary allylic amines, and sequentially one-pot Wittig olefination reactions were achieved successfully to give structurally diverse1,4-dienes. Compared with reported methods, such as Baylis-Hillman-type reactions of allylic halides,[3,3] rearrangement-olfenation reactions of phosphonium ylides, allylation-deacylation reactions of active methylene compounds, dual catalytic reactions by palladium/vanadium system, our method has the advantages with cheaper and more readily available raw materials, and also the method makes the reactions more efficient and easier to operate. Further, we studied the one-pot allylation-olfenation reactions of primary allylic amines with phosphonium salts. Finally, the key intermediate was isolated and characterized to investigate the corresponding reaction mechanism.Chapter3:Palladium-Catalyzed Stereospecific Substitution Reaction of Enantioenriched Allylic Alcohols with Sodium Sulfinates.Studies on the nucleophiles for palladium-catalyzed substitution reaction of enantioenriched allylic alcohols were rare. The reported nucleophiles are mainly focused on N-nucleophiles, O-nucleophiles and C-nucleophiles (only two cases). Especially, no S-nucleophiles have been applied in this reaction so far. Here, substitution reactions of enantioenriched allylic alcohols with sodium sulfinates as nucleophiles were conducted for the first time. And also the chirality-transfer efficiency achieved100%in our study. In a word, our study provided a simple and feasible method for the preparation of chiral allylic sulfones, especially the substituent α≠γ.