Study On The Hypervalent Iodine Reagent Mediated Oxidative Cascade Rearrangement And Related Reactions

In this thesis, we focused on the novel cascade oxidative rearrangement reactions mediated by hypervalent iodine reagents. Totally, we have developed six kinds of new cascade reactions with high efficiency.(1) The reaction of the readily available N-methyl-N-phenylcinnamamides with phenyliodine bis(trifluoroacetate)(PIFA) in the presence of Lewis acids provides a general and efficient assembly of a variety of 3-arylquinolin-2-one compounds. This novel approach features not only metal-free oxidative C(sp2)–C(sp2) bond formation, but also an exclusive 1,2-aryl migration. We did further investigation on the insight of the transformation from both experimental and calculational aspects and a reasonable mechanism was proposed.(2) A novel tandem metal-free oxidative aryl migration/C–C bond cleavage reaction, mediated by hypervalent iodine reagent, has been discovered. The presented transformation provided straightforward access to important???-and??-ketoesters derivatives from readily available acrylic derivatives via a concerted process of 1,2-aryl shift concomitant with C–C bond cleavage.(3) Reactions of cinnamic acids with PhI(OAc)2 in the presence of H2SO4 in DCE provided easy and direct access to the ??-ketodiacetate framework.This hypervalent iodine-mediated oxidative reaction involves a tandem sequence of aryl migration, insertion of an oxygen atom, decarboxylation and diacetoxylation.(4) PhICl2 in wet DMF was found to form an efficient system for realizing difunctionalization of various alkenes and olefinic derivatives possessing a wide range of functional groups. This novel methodology provides convenient access to either regioselective chloroformyloxylated products or??-chlorinated olefinic products, depending on the type of structure of the original unsaturated starting material.(5) A novel method for direct ?-functionalization of tertiary amines via NIS-mediated oxidative C–O bond formation, where NIS serves both as an oxidant and an iodination reagent, has been developed. The method provides an easy access to either iodinated or non-iodinated 1,2-dihydro-(4H)-3,1-benzoxazin-4-ones, depending on the nature of the reactant, via a regioselective transition metal-free approach.(6) A series of functionalized indenes bearing 1,3-dicyano groups were synthesized from electron-rich??-aryl ketonitriles in the presence of K3Fe(CN)6 and NaOAc, possibly through tandem process involving dimerization, heterolytic cleavage of carbon-carbon bond, intermolecular coupling and the subsequent intramolecular cyclization. The?2-arylindene compounds obtained possess good fluorescent properties.