Palladium-catalyzed α,β-dehydrogenation Of Bridged [4.3.1] Carbonyl Compounds

α,β-Unsaturated carbonyl compounds are versatile intermediates in the synthesis of pharmaceuticals and biologically active compounds.The efficient construction ofα,β-unsaturated carbonyl units consists of one of the most important issues in organic chemistry.An oxidative dehydrogenative strategy that introduces the chemical unsaturation into a preestablished molecular skeleton provides an appealing alternative method to access α,β-unsaturated carbonyl compounds.The previously reported dehydrogenation mainly focuses on the simple carbonyl compounds,and there are few reports on α,β-dehydrogenation of bridged compounds.Based on the reports of palladium-catalyzed α,β-dehydrogenation of carbonyl compounds,this thesis describes a preliminary exploration of the enantioselective dehydrogenation of [4.3.1]-bridged carbonyl compounds.The following three parts are mainly contained in this thesis.Part Ⅰ: The recent development for α,β-dehydrogenation of carbonyl compounds under the promotion of the non-metal system and the metal system is briefly presented.Part Ⅱ: Based on our previous research on palladium-catalyzed α,β-dehydrogenation of bridged compounds,the [4.3.1]-bridged compound with high oxidation state has been designed and synthesized to probe the construction of [4.3.1]bridgehead enone.Fllowed by the structural modification of the chiral ligands,the enantioselective construction of the [4.3.1] bridgehead enone has been investigated preliminarily.Part Ⅲ: On the basis of the above research,together with adjusting the original oxidation state of previous model compound with [4.3.1]-bridged structure,the enantioselective α,β-dehydrogenation of the [4.3.1]-bridged compound having low oxidation state has been achieved.The current study to some extent enriches the research of palladium-catalyzed α,β-dehydrogenation of carbonyl compounds,and also lays foundation for the synthesis of natural products containing structurally related bridged ring system.