Synthesis Of Two Categories Of Organosulfur Compounds Via C-X(X=C/N/B) Bond Cleavage And C-S Bond Construction

Organosulfur compounds widely exist in nature and are of importance in life science,medicine,food science and material science,etc.Hence,it is significant to furnish various organosulfur compounds in an efficient and concise manner through C-S bond formation.However,some longstanding problems stand out in the process of incorporating sulfur atom into frameworks of organic compounds,such as sulfur atom can poison transition metals due to its lone pairs that can strongly coordinate with 3d orbitals of transition metals;sulfur atom possesses multiple valences and can be readily oxidized which make sulfur-involved reactions uncontrollable;Conventionally,extremely smelly thiols as the most used reactants often make reactions run counter to what the green and sustainable chemistry expects.etc.In contrast,C-X（X=H/C/N/B）bond cleavage and its sulfenylation is one of the most useful strategy to give rise to organosulfur compounds.During my master’s studies,in order to solve afore-mentioned challenges in the preparation of valuable organosulfur compounds,by taking the advantages of C-X bond cleavage and C-S bond formation,my research works can be categorized into the following two aspects:（1）Synthesis of β-carbonyl thioethers via C-C/N bond cleavage and C（sp²）-S bond constructionWe report the first example of employing TEMPO and its analogues as C₃building block for the preparation of various β-carbonyl thioethers through C-C/N bond cleavage and activation of unstrained six-member rings under metal-and additive-free conditions.This transformation provides a new alternative to β-carbonyl thioethers.Preliminary mechanism studies indicate that this reaction involves a novel and complex reaction pattern,which can be divided into three processes:consecutive radical oxidation,skeleton rearrangement and C-S bond construction.In particular,both of the two starting materials serve as two different functions through the reaction process.（2）Synthesis of unsymmetrical disulfanes via C-B bond cleavage and C（sp³）-S bond constructionA versatile example of copper-catalyzed cross-coupling to a series of unsymmetrical disulfanes from commercially available boronic acids and Harpp reagent analogues by using phthalimide as a good carrier for disulfur transfer is developed.This reaction is performed under simple and pratical conditions and highlighted by the broad substrate scopes and good capatiability of diverse sensitive functional groups,even applicable for the transfer of aryl disulfur moieties（ArSS-）.Notably,this methodology can also be applied in the late-stage modification of bioactive scaffolds of coumarin,estrone,and captopril,which greatly show its robustness in the process of digging leading compounds.