Synthesis and reactivity of Chiral N-Heterocyclic Iodanes

Abstract

Hypervalent iodine compounds, in particular aryl-ʎ3-iodanes, have found widespread applications for many organic transformations. Their reactivities are comparable to highly oxidized period-6 metals, in particular Hg(II), Tl(III), and Pb(IV), with less toxicity. All these merits make hypervalent iodine compounds suitable reagents to perform a wide range of oxidative transformation reactions.

The first part of this thesis describes the efficient synthesis of novel triazole substituted chiral hypervalent iodine catalysts. It also describes the reactivity and selectivity of these new catalysts in different stereoselective oxidative transformations, such as Kita-spirocyclizations, the α-tosyloxylation of propiophenone, oxidative lactonizations, oxidative dearomtization of phenols and the oxidative rearrangement of allyl alcohols. The second part of the thesis describes the development of a novel enantioconvergent benzylic hydroxylation by employing a chiral iodine catalyst that fulfills a dual purpose as both oxidant and chiral ligand for a Cu co-oxidant. Finally, the enantioselective cyclization of unsaturated amides using chiral aryl iodides has been described, which has the facility to synthesize oxazoline derivatives. This method can be used to prepare natural products and biologically active compounds efficiently. Also, the asymmetric oxidative cyclization of naphthol compounds for the synthesis of chiral spirooxazolines has been described. These compounds have many applications in drugs and industrial applications.