Synthesis of novel N-heterocyclic carbene-palladium complexes and their catalytic activity

摘要

Chapter 1: Gives the reader a background on carbenes paying particular attention to N-heterocyclic carbenes (NHCs). The chapter describes NHC’s electronic and structural properties and their behaviour as ligands. The recent usage of NHC-palladium complexes as catalysts for cross-coupling reactions is explored.udChapter 2: Provides a background on NHC-palladium complexes bearing N-donors as throwaway ligands, highlighting the importance of throw-away ligands on catalytic activity. The chapter describes the preparation of a number of novel NHC-palladium complexes bearing throw-away ligands and the activity of (IPr*)PdCl2(TEA) in Buchwald-Hartwig aminations is explored.udChapter 3: Provides a background on the Mizoroki Heck reaction, focusing on the importance of charged intermediates in the process. Then reviews the current development of anionic NHC-palladium complexes in the literature. An account of the discovery and preparation of novel [(NHC)PdCl3[TBA] complexes and the catalytic activity of [(SIPr)PdCl3[TBA] in Mizoroki-Heck coupling reactions is given. A plausible Amotore-Jutand type mechanism is proposed which is supported by DFT calculations provided by research collaborators.udChapter 4: Provides a background on C-H activation reactions catalysed by palladium compounds with particular focus on acetoxylation reactions. The chapter describes the synthesis of [(NHC)PdCl2X][Y] complexes including the development of [(IMes)PdCl2OAc][TBA] and its performance in acetoxylation reactions. A proposed mechanism for the reaction of [(IMes)PdCl2OAc][TBA] is discussed, using experimental observations.