Catalytic Oxidations with ortho-Substituted Modified IBXs

Abstract

Abstract o-Iodoxybenzoic acid (IBX) is an oxidation reagent that has surged into prominence in the last two decades. It is cost-effective, environmentally benign, and readily prepared from o-iodobenzoic acid. However, its insolubility in common organic solvents and explosive attributes upon impact and heating are debilitating disadvantages. The development of modified IBXs (mIBXs) that exhibit improved solubility and enhanced reactivity, and obviate explosive attributes by judicious manipulation of the structure of IBX has been an incessant endeavor. In this account, common organic solvent-soluble mIBXs developed in our research group are collated with a discussion of the rationale underlying the design principles. Steric build-up around the iodoxolone moiety that is responsible for strong intermolecular interactions within the crystal lattice of IBX constitutes the key consideration in the design and development of modified λ5-iodanes that are reactive and sparingly soluble in common organic solvents. In situ generation of mIBXs from precursor iodo-acids in the presence of Oxone® permits their employment as organocatalysts for facile oxidative transformations. Reactive mIBXs generated in situ from precursor modified iodo-acids (mIAs, II) in the presence of Oxone® may offer unrivaled prospects for cost-effective oxidations. Applications of mIBXs, generated in situ or otherwise, for efficient oxidations are consolidated.1 Introduction2 Design and Synthesis of Modified IBXs and their Precursors Iodo-Acids3 Catalytic Oxidations with Modified IBXs3.1 Oxidation of Alcohols3.2 Oxidation of 1,2-Diols3.3 Conversion of Diols into Lactones3.4 One-Pot Oxidative Cleavage of Olefins3.5 One-Pot Transformation of Olefins into α-Bromo- and α-Azidoketones4 Conclusions