Studies On Transition-Metal Catalyzed Diazo Compounds Involved Cascade Reactions

Diazo compounds have been found wide applications in modern synthetic organic chemistry.Transition-metal catalyzed reactions of diazo compounds can give metal carbenes,which will then undergo diverse reactions.Moreover,transition-metal catalyed domino reations have been outsanding due to its characteristic feature of atomic economy and high synthetic efficiency,which has also been widely investigated in organic transformation.In this cascade reaction,transition-metal catalyed tandem reactions of diazo compounds are unrivaled in the ablility to provide rapid access to architecturally complex molecules,which might have some potential biological activity,from retativly simple acyclic starting materials.The dissertation is focused on a stereodivergent synthesis of five-membered N-heterocycles,such as 2,3-dihydropyrroles,and 2-methylene and 3-methylene pyrrolidines,through copper and rhodium-catalyzed tandem annulation of diazo compounds with amino alkynes and involves the trapping of in stiu formed intermediates.The content of this text will be divided into two parts:Part one: An efficient methodology to access of 2,3-dihydropyrroles and 2-methylene pyrrolidines by the reaction of amino alkynes with diazo compounds proceed by allenoate formation and subsequent intramolecular hydroamination under CuCl-catalyzed conditions has been developed.The intramolecular hydroamination of amino allenoates gives different cyclization products compared with those described in previous reports.Part two: We have been studied a rhodium-catalyzed cascade reaction of carbenoid insertion into the N-H bond and subsequent Conia-ene cyclization,which provides an alternative way to synthesize various3-methylene pyrrolidines.The N-H insertion intermediate has been successfully separated,which verify its correctness.