Study On Zinc Powder Promoted "One-pot" Allyl Substitution Reactions

Allylic alkylation using carbon nucleophiles has developed into an efficient andimportant carbon-carbon bond forming method in organic synthesis; especiallynumber asymmetric variants provided valuable tools for the formation of tertiary andquaternary stereocenters. It has now been widely used in total synthesis of naturalproducts or synthesis of complex biologically active molecules. On the other hand,"one pot" reactions and transition-metal free reactions have been the topics in modernorganic syntheses to avoid the time-consuming, waste-producing manual purificationoperations and cost-demanding process. As a rival to this traditional "stop-and-go"approach,"one pot" reactions seem more economical, and to the benefit of industrialprocesses. In this paper, a zinc metal promoted, catalyst-free, one-pot allylicalkylation reactions were firstly disclosed.The thesis mainly consists of the following three parts:Chapter one: Copper-catalyzed Enantioselective Allylic SubstitutionThis chapter presents an overview of tremendousstudies towards thedevelopment of an "ideally" active catalyst achieving high regio-andenantioselectivities. The comparative reactivity and generality of peptides,phosphorus, as well as N-heterocyclic carbenes based catalysts are discussed in thefirst part. Then, relevant scope and synthetic applications are reviewed. Noteworthily,this chapter is restricted to C–C bond formation processes, excluding C–B and C–Sibond formations.Chapter two: Zinc Metal Promoted One-Pot Allyl Substitution ReactionsIn this chapter, we provided a new synthesis method of1,5-dienes and discussedthe influence of reaction conditions on the reaction yields after doing researches onreactions of1,3-diphenylallyl acetate, allylic bromide and zinc powder. This processprovided a very convenient and efficient method for preparation of1,5-dienes, whichare the important intermediate in organic synthesis and basic unit in some naturalproducts. Another advantage of this method is that there is no need to prepare theallylic zinc bromides in advance. Chapter three:"One-pot" synthesis of MDL-100907intermediateIn this chapter, we provided a new synthesis method of MDL-100907intermediate——N-methoxy-N-methyl-1-the tosyl piperidine-4–amide, anddiscussed the influence of reaction conditions on the reaction yields. This is a neweffective way to prepare N-methoxy-N-methyl-1-the tosyl piperidine-4–amide because of the mild conditions, low cost, simple operations, short reaction time,and high yields. Most importantly, it avoids the drawbacks of preparation ofphosphoramidite in advance, which is unstable and difficult separation.