Sodium Decatungstate-Visible Light Induced C(sp~3)-H Acylation

Acyl as a common functional group which exists in many natural products,drugs,and materials,and is broadly applied to construct of C-C bonds and alcohols in organic chemistry.Due to its common chemical structure and wide application value,it has attracted researchers’attention.For the moment,most utilized strategies for acylation mainly rely on the prefunctionalization of carbonyl or halogen and few strategies can directly transform strong aliphatic C-H bonds into acyl groups.The decatungstate as a photocatalyst has high energy excited state.Under near-UV light,the C(sp~3)-H bond can be activated by hydrogen atom transfer(HAT)process to afford carbon-centered radical and then achieve various C(sp~3)-H functionalization.Because of the high activation energy and good site-selectivity,the decatungstate has been widely used in organic synthetic chemistry.The research progress of decatungstate-photocatalyzed C(sp~3)-H functionalization has been reviewed in this paper.Inspired by these research,we have performed the photocatalyzed acetylation.The generation of the cyclohexyl radicals from decatungstate-photocatalyzed hydrogen atom transfer could react with methyl sulfonyl oxime to realize the C(sp~3)-H acylation.Various methyl sulfonyl oximes were preparedly synthezed by ourselves p-Trifluoromethyl phenyl methyl sulfonyl oxime was found that can improve the reaction efficiency and has good site selectivity.The advantage of our strategy is that a various series of unactivated hydrocarbons are used as substrates efficiently acetylated into the corresponding alkyl ketones,with the excellent site-specificity and regioselsctivity.Moreover,this protocol is further characterized by the various acyl group,which was effectively installed.The broad practicability of this strategy is illustrated in the late-stage functionalization of complex natural products and pharmaceutically relevant molecules.