Visible-light-driven Radical Transformation Of Dithiocarboxylate Derivative Anions

Dithiocarboxylate derivative anions have attracted extensive attention of scientists due to their important significance in various fields such as biomedical chemistry and materials science.In recent years,the development of visible-light-driven photoredox catalysis provides a facile and mild route for the radical transformation of dithiocarboxylate derivative anions.Due to their low oxidation potential,dithiocarboxylate derivative anions can be easily oxidized to dithiocarboxylate thioradicals,thus can act as radical precursors to participate in the synthesis of organosulfur compounds and catalyze radical transformations.Although many important progresses have been made,most of these methods do not change the structure of the dithiocarboxylate groups.On the other hand,visible-light-driven deoxygenation/desulfurization of phosphoranyl radical provides an efficient route for the cleavage of C-O and C-S bonds.However,the radical transformation reactions of dithiocarboxylate derivative anions using the deoxygenation/desulfurization of phosphoranyl radical were still less explored.This dissertation presents the study on the visible-light-driven radical transformation of dithiocarboxylate derivative anions upon phosphoranyl radical-mediated deoxygenation/desulfurization.The detailed research work are listed as follows:(1)Xanthate salts,which can be efficiently generated from alcohols and carbon disulfide in the presence of a base,can be used as an activated functional group to obtain alkyl radicals under the action of visible light photoredox catalysis and the desulfurization of phosphine,then react with electron-deficient alkenes to realize deoxygenative alkylation of alcohols.This method can be effectively applied to diverse primary,secondary and tertiary alcohols,Moreover,it can effectively identify the hydroxyl groups of primary,secondary and tertiary alcohols in diols,and selectively realize their deoxyalkylation.This strategy can also be applied to late-stage modification of natural products and drugs,provides an important platform for visible-light-driven deoxygenative radical transformation of alcohols under visible-light photoredox catalysis.(2)Xanthate salts,which can be efficiently generated from alcohols and carbon disulfide in the presence of a base,can be used as radical precursors to obtain excited xanthates under visible light excitation,then react with alkenyl sulfones and allyl sulfones to realize deoxygenative alkenylation/allylation of alcohols with high efficiency and chemoselectivity under the action of the desulfurization of phosphine without photocatalyst.This method not only has mild reaction conditions,broad substrate scope,but also has good chemical selectivity for polyols,which provides a new approach for the conversion of alkyl radicals.(3)Dithiocarbamates,which can be efficiently generated from amines and carbon disulfide in the presence of a base,can be used as radical precursors to obtain aminothioacyl radicals under the action of visible light excitation and the desulfurization of phosphine,then react with electron-deficient alkenes to develop visible-light-driven multicomponent reactions of amines,carbon disulfides,and electron-deficient olefins,which constructs structurally diverse thioamide derivatives in the absence of photocatalyst.This strategy can be applied to a variety of cyclic amines and chain amines,as well as various functional groups,which solves the problems of special sulfur source,high temperature and narrow substrate range in the classical synthesis method of thioamide derivatives,and provides a new way for the synthesis of thioamide derivatives.This dissertation used dithiocarboxylate derivative anions,as radical precursors to realize visible-light-driven radical transformation reactions upon the desulfurization of phosphoranyl radical.By utilizing this strategy,visible-light-driven deoxygenative alkylation,alkenyl/allylation of alcohols,and synthesis of structurally diverse thioamide derivatives have been achieved.These methods can be further applied in the late-stage modification of natural products and drug molecules,providing a new platform for visible-light-driven radical transformation of dithiocarboxylate derivative anions.