Twist Does a Twist to the Reactivity: Stoichiometric and Catalytic Oxidations with Twisted Tetramethyl-IBX

Abstract

The methyl groups in TetMe-IBX lower the activation energy corresponding to the rate-determining hypervalent twisting (theoretical calculations), and the steric relay between successive methyl groups twists the structure, which manifests in significant solubility in common organic solvents. Consequently, oxidations of alcohols and sulfides occur at room temperature in common organic solvents. In situ generation of the reactive TetMe-IBX from its precursor iodo-acid, i.e., 3,4,5,6-tetramethyl-2-iodobenzoic acid, in the presence of oxone as a co-oxidant facilitates the oxidation of diverse alcohols at room temperature.

Evolution of N‐Heterocycle‐Substituted Iodoarenes (NHIAs) to Efficient Organocatalysts in Iodine(I/III)‐Mediated Oxidative Transformations

“…However, originally, the “hypervalent twist” was proposed in an early work by Goddard and co‐workers for λ 5 ‐iodanes, as being the structural rational for the enhanced reactivity of 2‐iodoxybenzoic acid 5 in alcohol oxidations . This was experimentally further confirmed by Moorthy and co‐workers …”

“…[29] This was experimentally further confirmed by Moorthy and co-workers. [30,31] Very recently, Muñiz, Postnikov as well as our group systematically investigated N-heterocycle-stabilized λ 3 -iodanes (NHIs, Figure 2). [32][33][34][35] These (pseudo) cyclic aryl-λ 3 -iodanes can be readily synthesized on a gram scale through robust heterocycle chemistry allowing a fast variation of the N-heterocyclic ligand.…”

Friedel-Crafts chemistry. Part 50. Convergent and diversity-oriented constructions of polycyclic quinolines via Friedel-Crafts and Beckmann ring enlargement approaches

“…These amides were hydrolyzed to the corresponding substituted (7-aminoquinolin-8-ylthio)alkanoic acids 8a-c with NaOH in refluxing EtOH, which were subsequently converted to 7-bromoquinolin-8-ylthioalkanoic acids 9a-c by Sandmeyer reaction. 37 Subsequent treatment of halo-acids 9a-c with various aromatic tosylated amines (PhNHTs or N-tosylpyridin-2-amine or TsNHCH2Ph) in the presence of K2CO3 in DMSO solution furnished (7-(N-phenyl-N-tosylamino)quinolin-8-ylthio)alkanoic acids (10a-i) in good overall yields. Table 1).…”

A theoretical study on diastereoselective oxidative dearomatization by iodoxybenzoic acid

“…rac indicates that racemic compounds are obtained Oa then undergoes oxidative dearomatization itself. The mechanism initially proposed in [23] is founded on the results of a detailed theoretical study by Su and Goddard [38], who cast light on the so-called hypervalent twist (defined as "a coordinated motion of ligands" that brings the oxo group into the iodoxyenzoic plane and the alcohol to be oxidized out of the plane), which is thought to be the rate-limiting step and has been the subject of several subsequent important studies [52,53].…”