Study On The Oxidative Cascade Reaction In Copper Salts And TEMPO Systems

One of the major challenges to be solved in modern organic synthesis is how to synthesize molecules with potential application value in the fields of materials,biology,pharmaceuticals and natural products with the efficient and convenient,cheap and green catalytic processes.Oxidative cascade reactions provide a fast and simple idea in the chemical synthesis,especially in the reverse synthesis of high bioactive molecules.It has many advantages such as readily accessible substrates,high efficiency and atom-economyin one-pot manner,and could rapidly enrich the complexity of molecules.As a common transition metal,copper salts holds the advantages of rich source,low price and low toxicity in organic synthesis.Meanwhile,TEMPO as a cheap and stable nitroxide free radical has been widely used in single-eletron transfer processes.In this context,the development of oxidative dehydrogenation reactions and multicomponent oxidation cascade reactions with copper and TEMPO catalytic system holds great research significance and synthetic value.Recent reseaech advancement of oxidative dehydrogenation of polar C-X unsaturated compounds and multicomponent oxidation cascade reactions are briefly reviewed at first chapter.In the chaper two,our research work in intermolecular multiple dehydrogenative cross-couplings of ketones with boronic acids and amines as nucleophiles,is discussed.The catalytic system is combined with Cu O as cheap metal catalyst,TEMPO as oxidant and radical initiator,and tert-butyl hydroperoxide as the hydrogen acceptor.Various ?-functional unsaturated ketones as product,such as ?,?-unsaturated ketones and enaminones,could be obtained efficiently.Significantly,meta-functionalized phenols,which are difficult to access by other methods,could be readily obtained by using this methodology.The reaction is appreciated for its simple conditions and achieving rapid molecular complexity through multiple dehydrogenative couplings.In the chaper three,an oxidative cascade that involves multicomponent reaction comprising a terminal alkyne,2-amino N-heterocycle and benzyl or allylic bromide,delivering densely functionalized pharmaceutical molecules with imidazole derived heterocycles,is described.This reaction features mild condition,green oxidant(molecular oxygen),and readily available starting materials,which makes the overall synthesis applicable in the quick access to relevant imidazo fused heterocycles through the construction of two C-N bonds and one C-C bond.