Studies On Preparing Aldehydes And Ketones Through C-H Oxidation

Aldehydes and ketones are widely used in organic synthesis,fine chemicals,and materials;therefore green and efficient preparation of aldehydes and ketones is very important.Traditional synthesis of aldehydes and ketones relies on the reduction of carboxylic esters with hydrosilane,hydroformylation or controlled oxidation of alcohols and aromatic compounds.However,these methods have certain issues in terms of low functional-group-tolerance,the toxicity and requirement of pre-functionalization of starting materials.C-H bonds are ubiquitous in natural products and the synthetic world.Direct functionalization of C-H bonds could reduce the synthetic steps and improve the reaction efficiency of target molecules.This paper focuses on the synthesis of aldehydes and ketones via transition metal-free aerobic oxidation of C-H bonds.The specific research contents and results are as follows:?1?A metal-free and radical-free synthesis of heteroaromatic aldehydes was developed through aerobic oxidation of methyl groups in an I ₂/DMSO/O₂ catalytic system.Under the reaction conditions,various functional groups such as methoxy,aldehyde,ester,nitro,amide,and halo?F,C l,Br?groups were well tolerated.The bioactive compounds like chlorchinaldin derivative and papaverine were also oxidized to the corresponding aldehydes and ketones.This reaction provided an efficient method for preparing the valuable heteroaromatic ald ehydes.?2?A new method for the preparation of dicarbonyl compounds has been developed.Promoted by iodine,the monoketones can be oxidized to the dicarbonyl compounds in dimethyl sulfoxide solvent through oxidation of alpha-C-H bonds.