Hypervalent iodine-catalyzed oxylactonization of ketocarboxylic acids to ketolactones (original) (raw)
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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.
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.
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.
Iodine catalysis: A green alternative to transition metals in organic chemistry and technology
Resource-Efficient Technologies, 2015
Iodine and compounds of iodine in higher oxidation states have emerged as versatile and environmentally benign reagents for organic chemistry. One of the most impressive recent achievements in this area has been the discovery of catalytic activity of iodine in numerous oxidative transformations leading to the formation of new CO , C-N, and CC bonds in organic compounds. These catalytic transformations in many cases are very similar to the transition metal-catalyzed reactions, but have the advantage of environmental sustainability and efficient utilization of natural resources. Iodine is an environmentally friendly and a relatively inexpensive element, which is currently underutilized in industrial applications. One of the main goals of this review is presenting to industrial researchers the benefits of using catalytic iodine in chemical technology as an environmentally sustainable alternative to transition metals. The present review summarizes catalytic applications of iodine and compounds of iodine in organic synthesis. The material is organized according to the nature of active catalytic species (hypoiodite, trivalent, or pentavalent hypervalent iodine species) generated in these reactions from appropriate pre-catalysts. Numerous synthetic procedures based on iodine(III) or iodine(V) catalytic species in the presence of hydrogen peroxide, Oxone, peroxyacids or other stoichiometric oxidants are summarized. A detailed discussion of catalytic cycles involving hypervalent iodine, hypoiodites, and other active intermediates is presented.
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...