Iron And Thiyl Radical Co-catalyzed Selective Oxidative Cleavage Of C=C Bonds And Selective Oxidation Of Sp~3 C-H Bonds With Oxygen

This thesis focuses on the development of efficient and green catalytic systems based on iron and thiyl radical co-catalyzed oxidation protocols using oxygen as an oxidant.Selective oxidative cleavage of C=C bonds as well as selective oxidation of sp³C_?-H bonds of ethers and amines has been achieved using these catalytic systems.The mechanistic studies of these protocols were also conducted.Part 1:Iron and thiyl radical co-catalyzed selective oxidative cleavage of olefin with oxygenOxidative cleavage of alkenes using 1,1'-bis?diphenylphosphino?ferrocene and bismuththiol as co-catalysts under 1 atm of O₂ has been achieved.The reaction proceeds with high chemo-and regioselectivity and a broad substrate scope,as well as excellent functional group compatibility.This method could potentially be employed for the late-stage oxidation during the synthesis of bioactive compounds,and thus provide a good opportunity for applications in drug discovery and development.Radical process of the reaction was confirmed by radical inhibition and EPR experiments.Mechanistic studies uncovered a vital dioxetane intermediate which might be involved in the reaction.Both catalysts played important roles,as verified by the control experiments.The reaction could be easily scaled up to 25 grams with good yields,illustrating potential for broad synthetic applications.Part 2:Iron and thiyl radical co-catalyzed selective oxidation of sp³ C_?-H bonds of ethers with oxygenTransformation of ethers to the corresponding esters through selective oxidation of sp³ C_?-H bonds has been achieved with a catalytic system comprised of1,1'-bis?diphenylphosphino?ferrocene and phenyl disulfide with 1 atm of O₂.This reaction showed high regioselectivity and excellent functional groups tolerance.The high regioselectivity of this reaction derived from the selective generation of benzylic carbon-centered radical among the different sp³ C_?-H bonds by a highly reactive thiyl radical via a hydrogen abstraction process.Isotope labeling experiments revealed that the oxygen atom was most likely derived from molecular oxygen.Part 3:Iron and thiyl radical co-catalyzed selective oxidation of sp³ C_?-H bonds of amines with oxygenAn oxidation method to prepare lactams from the corresponding amines using O₂?1 atm?as the oxidant,?dimethylaminomethyl?ferrocene as the catalyst and phenyl disulfide as cocatalyst was developed.This transformation uses a catalytic amount of Na₃PO₄ as an additive.Such reaction is environmental-friendly and features high atom economy and a broad substrate scope.In addition,selective oxidation of cyclic amine derivatives prepared from pharmaceutically important molecules and amino acids also proceeded smoothly,which provides a novel approach for the synthesis of natural products and bioactive molecules.Isotope labeling experiments revealed that the oxygen atom was derived from molecular oxygen.