Oxidative Breakdown of Iodoalkanes to Catalytically Active Iodine Species: A Case Study in the α‐Tosyloxylation of Ketones (original) (raw)
International Academic Publishing House, 2022
Abstract: Molecular iodine is an eco-friendly, powerful catalyst and plays an important role in pharmaceutical, medicinal and organic chemistry. For a long time, molecular iodine has been hugely applied in carbohydrate chemistry. Due to the huge application of molecu-lar iodine in oxidation, cross coupling and cyclisation reactions, it has emerged as an ele-gant tool in organic synthesis. Earlier I discussed (Biswas, 2021) on iodine mediated cas-cade oxidative functionalisation, cyclisation and annulation reactions. In this review, I de-scribe the utility of iodine catalysed tandem oxidation, cross coupling, and cyclisation reac-tions in organic synthesis. Molecular iodine catalysed mild oxidative conditions yielding desired products, and oxidising techniques applied to the efficient synthesis tolerate a wide range of starting materials with aryl or alkyl replacements. These reactions were carried out as a one-pot or multi-step eco-friendly process that could be used for a wide range of drug and pharmaceutical product synthesis.
Direct α-iodination of ketones using iodine/SeO2
Tetrahedron Letters, 2000
A satisfactory yield one-pot synthesis of various α-mono iodoketones 2 was achieved by iodination under oxidative conditions of ketones 1. The monoiodination of different aliphatic or cyclic ketones (1-tetralones) showed the quite general applicability of the method.
Metal-free one-pot oxidative conversion: Molecular Iodine Mediated Oxidation Organic Reactions
International academic Publishing House, 2022
Various oxidative compounds such as aldehyde, ketone ester, and acids can be produced in large yields by an effective iodine-mediated oxidative reaction of organic molecules. Molecular iodine is a generally available and commercially extremely inexpensive substance that induces oxidative esterification. With the comparison with different Brønsted acid catalysis, molecular iodine or iodophilic activations proceed the reaction onto a deoxygenation pathway. With only a few mol% of I2, the oxidation occurs very quickly at room temperature. This approach could also be used to transport different benzil derivatives from nonactivated alkynes, such as diaryl acetylenes. Molecular iodine with several mild reagents such as aq. NH3, ∼30% aq. H2O2 and DMSO might be used to convert various one degree alcohols, particularly benzylic alcohols, into the corresponding aromatic amides in sufficiently high yields in a one-pot method. Similarly, by treating different benzylic chloride, bromide and iodide with a molecular iodine oxidation medium, the corresponding aromatic amides may be prepared in a one-pot method. The reactions in this section include transformation of several compounds into their respective oxidative products with the metal-free one-pot oxidative.
Hypervalent iodine (V) catalyzed reactions
Arkivoc
The chemistry of hypervalent iodine compounds has been widely recognized in the synthetic community. The utilization of hypervalent iodine compounds as stoichiometric reagents as well as catalysts has tremendously been studied in recent decades. Hypervalent iodine (V)-catalyzed reactions are proven to be versatile catalytic systems to access various oxidative transformations. In this review, the versatility of hypervalent iodine (V)catalyzed reactions have been discussed in detail. This review highlights the oxidation of various substrates using catalytic amounts of o-iodoxybenzoic acid (IBX), modified IBX derivatives, o-iodoxybenzenesulfonic acid (IBS), recyclable iodine (V), and non-cyclic/pseudocyclic iodine (V) compounds.
2‐Iodoxybenzoic Acid Tosylates: the Alternative to Dess–Martin Periodinane Oxidizing Reagents
Advanced Synthesis & Catalysis, 2017
Two powerful hypervalent iodine(V) oxidants, DMP‐OTs (1‐tosyloxy‐1,1‐diacetoxy‐1H‐1λ5‐benzo[d][1,2]iodoxol‐3‐one) and IBX‐OTs (1‐tosyloxy‐1‐oxo‐1H‐1λ5‐benzo[d][1,2]iodoxol‐3‐one) show high reactivity in the oxidation of structurally complex primary and secondary alcohols, which are highly functionalized polyketide or terpene fragments or steroids. The yields of the corresponding carbonyl compounds are even higher for the protocol that uses pyridine as additive. The oxidations proceed very rapidly at room temperature leaving the protective groups and π‐systems intact and affording the corresponding carbonyl compounds in good to excellent yields. Moreover, IBX‐OTs is an efficient reagent for the oxidative dehydrogenation of steroidal alcohols to the corresponding enones.magnified image
Oxidase Catalysis via Aerobically Generated Hypervalent Iodine Intermediates
Development of sustainable oxidation chemistry demands strategies to harness O<sub>2</sub> as a terminal oxidant. In particular, oxidase catalysis, in which O<sub>2</sub> serves as a chemical oxidant without necessitating oxygen incorporation into reaction products, would allow diverse substrate functionalization chemistry to be coupled to O<sub>2</sub> reduction. Direct O<sub>2</sub> utilization must overcome the intrinsic challenges imposed by the triplet ground state of O<sub>2</sub> and the disparate electron inventories of four-electron O<sub>2</sub> reduction and two-electron substrate oxidation. Here, we generate hypervalent iodine reagents, a broadly useful class of selective two-electron oxidants, from O<sub>2</sub>. Synthesis of these oxidants is achieved by intercepting reactive intermediates of aldehyde autoxidation. The use of aryl iodides as mediators of aerobic oxidation underpins an o...