Visible-light Promoted Reactions Of Bromoalkynes With Anilines Or Aalcohols Under Photocatalyst-free Conditions

In recent years,visible-light-promoted organic reactions,as a new and efficient synthetic method,have been widely used in organic transformation.This method has mild conditions and with high efficiency,is accord with the concept of green chemistry.Simple alkyne derivatives are easily availuable synthetic precursors,and applied in diverse types of organic chemical reactions.However,how to construct a complicated molecule only under visible-light irradiation by using alkyne derivatives as starting materials is still a very challenging subject.This paper mainly focuses on visible-light driven reactions of bromoalkynes and aniline or alcohols under photocatalyst-free conditions.Details are as follows:1.Visible-light triggered tandem oxidative amidation of bromoalkynes with anilines for the synthesis of?-ketoamides.This transformation could be furnished via C-N cross-coupling and an oxidation of C?C bond procedures without an external photocatalyst and additives at ambient conditions,and a wide range of?-ketoamides were obtained in good yields.A possible mechanism was investigated by control experiments.2.The chemoselectivity of visible-light-promoted coupling reactions of bromoalkynes with alcohols can be controled by changing reaction atmosphere.Swiching the type of gas atmosphere in which the coupling reactions takes place,the products propargyl alcohols and?-ketoesters can be selectively synthesized from easily available starting materials.N₂favored propargyl Alcohols via a direct C-C coupling process,whereas O₂resulted in generation of?-ketoesters through an oxidation of C?C/C-O coupling pathway.It is should be noted that both these chemoselective photopromoted synthetic-platform are metal-,photocatalyst-and additive-free and furnished with good functional group tolerance.