Synthesis Of α,α-Dithioketones And α-Ketoamides Based On Methyl Ketones

α,α-Dithioketones have a wide range of applications in the fields of organic synthesis and chemical biology.The construction of methyl disulfide can be used as angiotensin converting enzyme inhibitor,biological coupling reagent,key intermediate in organic transformation and photocatalytic reagent.The literatures report many synthetic methods on the formation of C-S single bonds on the saturated carbon atoms at theα-position of the carbonyl group.The use of non-prefunctionalized substrates directly produces a dithiolation reaction at theα-position of the carbonyl group,and simultaneously generates two C-S is less reported.Therefore,we expect to develop a simple and efficient new route toα,α-dithioketone compounds.The contents of this thesis are as follows:In chapter one,the research significance of bifunctionalized compounds onα-position carbonyl carbon atoms and the main synthetic methods reported in the literatures is systematically summarized.It includesα-position dihalogenation,dioxyalkylation,biaromatization and dithiolation of the carbonyl compounds.Based on the summary of the literatures and our previous research resluts,the research ideas and content are proposed.In chapter two,in the KOH-DMSO strong base system,using disulfide as the sulfur source,the selective dithiolation ofα,α-dithioketones was realized at room temperature,and a series of carbonylα-position disulfides were prepared.This reaction simultaneously forms two C-S bonds on sp³-hybridized carbon atoms.Diselenides are also suitable for this reaction,yielding the corresponding diselenated products at theα-position of the carbonyl group.Acetophenone and two different thioethers can give corresponding crossing reaction products.In this chapter,the reduction of the carbonyl group to the hydroxyl group of the product and the reaction mechanism are also preliminarily discussed.A total of 34 compounds were synthesized,all of which were characterized by ¹H NMR,¹³C NMR,IR and MS.The structure of the product II-3g was further confirmed by X-ray single crystal diffraction.This reaction has the advantages of readily available non-prefunctionalized substrates,good functional group tolerance,excellent yields as well as metal-free conditions.Compared with the known methods,this route has obvious advantages in the synthesis ofα,α-dithioketones.In chapter three,the research and application ofα-ketoamides in various natural products,polymers and organic synthetic chemistry is described,and the synthetic methods ofα-ketoamides are summarized.Based on the research results in chapter two,the reaction ofα,α-dithioketone with cyclic secondary amines（or primary aromatic amines）as substrates in acetonitrile at 70 ^oC gives a series ofα-ketoamides,and a preliminary analysis of the possible reaction mechanism was proposed.These synthesized compounds are characterized by ¹H NMR,¹³C NMR,IR and MS.