The Investigation Of Rearrangement Of Ynamides & Rh(?)-Catalyzed Cyclizations

Ynamides,a type of unique alkynes,exhibit dual nucleophilic and electrophilic properties and serve as versatile building blocks in heterocycles synthesis.In this thesis,we developed a rearrangement reaction and multicomponent reaction of ynamides.Rh(?)catalyzed cyclization has become an important approach to heterocyclic compounds.In this thesis,we developed a[4+2]cyclization of oximes and alkenes for accessing isoquinolines,and a[4+2]cyclization of aryl amides with diazonaphthalen-2(1H)-ones for accessing lactones.In addition,we also developed a Iridium-catalyzed cycloaddition of azides and 2-hydroxypheyl alkynes with high efficiency and regioselectivity.The main contents of this thesis are as follows:(1)?-keto acids react with ynamides give the adduct.The activated ketocarbonyl group is added by the olefin.An intramolecular addition following decarboxylation and rearrangement gave the ?-keto imides in excellent yields with the release of CO.Furthermore,we conducted an isotope-labeling reaction and a GC analysis to gain an insight into the reaction mechanism.Using ynamides acting as C2 synthetic module,we developed a one-pot multicomponent reaction involving ortho-hydroxy benzhydryl alcohols,carboxylic acids and ynamides.The adduct intermediates of ynamides and carboxylic acids can react with ortho-Quinone methides to obtain bifunctional products in one-pot reaction.(2)Rh(?)-catalyzed C-H activation/cyclization of oximes with alkenes for regioselective synthesis of isoquinolines.And the synthetic utility of this protocol was applied to the total synthesis of moxaverine.We provide a method for accessing lactones and oxazinones with benzamides and diazonaphthalen-2(1H)-ones.(3)We developed a novel iridium-catalyzed hydroxyl-enabled cycloaddition of azides and alkynes to synthesize a series of triazole compounds in high yield and high selectivity.The process is featured broad substrate scope,mild reaction condition and good biocompatibility.Furthermore,the late-stage divergent transformation was conducted to synthesize a series of complex triazole compounds.