Anion Relay Chemistry Based On Activited Cyclopropane And Its Application In Heterocyclic Synthesis

Anion relay chemistry as an efficient organic tactic is widely used in the synthesis of heterocyclic compounds with biological activity and natural products. Untill now, all the research on anion relay reaction was based on Brook arrangement. Development the chemistry via non-Brook rearrangement anion relay reaction is the pursuit of organic chemists.Cyclopropane derivatives were extensively explored in organic synthesis due to the unique structural property and reactivity. In this thesis, we have devolp ed an array of non-Brook rearrangement anion relay chemistry by designing hi ghly-founctionalized cyclopropane derivatives for the synthesis of diverse hetero cyclic compounds. The mechanisms of these new reactions are also investigated in details. These methods have apparent advantages, such as readily available starting materials, efficiency and atom and step economy.The thesis is divided into seven chapters. In the first chapter, the development of anion relay chemistry and its application in the synthesis of natural products is reviewed. In chapter two, the application of cyclopropanes chemistry in the organic synthesis is systematically summarized and classified. The thesis proposal is presented in chapter three.Chapter 4 developed an aza-oxy-carbanion relay via tandem Michael additio n/ring opening of cyclopropane and recyclization/carbanion migration/electrophile trapping by the utilization of 1-cinnamoylcyclopropanecarboxamides for the synthesis of biologically active bicyclic furo[3,2-c]pyridinone compounds in a facile and efficient way. This cascade reaction represents the first example of anion relay chemistry via non-Brook rearrangement. An efficient method for the synthsis of biscyanoethylated furo[3,2-c]-pyridinones via multi-component anion relay was also developed in the further work.Chapter 5 introduced an organocatalyzed anion relay cascade based on 1-ci nnamoylcyclopropanecarboxamides. The reaction provided a simple, efficient and atom economy new method for the synthesis of biologically important 2,3-dihy drofurans via intermolecular Michael addition initiated enolate anion-triggered ring-opening of the cyclopropane.Chapter six developed a novel and efficient anion relay reaction for the construction of γ-lactams with an all-carbon quaternary center via a DABCO catalyzed reaction of EWG-activated cyclopropanecarboxamides and electron-defi cient alkenes. The process involves sequential ring-opening of activated cyclopr opanes/intermolecular Michael addition/1,5-H shift and intramolecular aza-cycliza tion.Chapter seven disclosed the cyanation of α, β-unsaturated enones by employing malononitrile as the organic cyanide source, which proceeds efficiently under mild conditions. This method avoided the use of transition metal catalyst/highly toxic cyanide reagent and harsh conditions generally adopted in the conventional cyanation reaction.