Studies On Pd(Ⅱ)-Catalyzed Decarboxylative Coupling And CAN Initiated O-Alkylation Reactions

This thesis mainly describes Pd-catalyzed decarboxylative cross-coupling reactions, which involve the decarboxylative allylation and the Heck-type coupling reaction, and cerium(â…£) ammonium nitrate (CAN) initiated O-alkylation of oximes with N-vinyl lactams. It is divided into four major sections as following.Chapter 1 reviews the recent development of decarboxylative coupling recations catalyzed by transition-metal catalysts. Three aspects of transition-metal-catalyzed decarboxylative Heck reactions, decarboxylative biaryl compounds formation, and transition-metal-catalyzed other decarboxylative coupling reactions are introduced in this section.In Chapter 2, the methods for allylation of arenes are involved. A novel approach to the Pd-catalyzed direct decarboxylative allylation of arenes using aromatic carboxylic acids with allylic halides is given, which would provide an attractive alternative for preparing allylated arenes. The possible mechanism for this reaction is also dicussed here. The electron-rich aromatic carboxylic acids with at least one ortho substituent are effective substrates under the typical reaction conditions, whereas the electron-deficient ones disfavor the reaction. This approach offers several advantages over the past ones like low costs of starting materials, short reaction time, safe byproducts, and the absence of hazardous and unstable organometallics reagents. It would be attractive.The development of Heck reaction has been precisely reviewed in Chapter 3 first. Then an efficient Pd-catalyzed decarboxylative Heck reaction using aromatic carboxylic with allylic esters and ethers as starting materials is demonstrated. Finally, we also depict the modification of the typical reaction conditions, substrate scopes, and the possible mechanism for this reaction.Chapter 4 describes the synthetic applications of CAN as catalyst and the traditional synthetic protocols for oxime ether derivatives. An O-alkylation of various aldoximes or ketoximes with N-vinyl lactams initiated by a catalytic amount of CAN, giving the corresponding oxime ether derivatives developed by us is demonstrated. An assmued reaction mechanism is also given in this section.