Iodine electrophiles in stereoselective reactions: recent developments and synthetic applications

French, Andrew N.; Bissmire, Stewart; Wirth, Thomas

doi:10.1039/b310389g

Cited by 248 publications

(95 citation statements)

References 35 publications

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“…[30b, 36] The reaction can be catalyzed to improve the regioselectivity, [37] and has been employed in numerous total syntheses as a reliable way to create new stereocenters. [36,38] The use of a chiral organocatalyst enables highly enantioselective iodolactonization to be achieved (Scheme 1 b). [39] Hypervalent iodine reagents are mild and powerful oxidants for a range of functional groups.…”

Section: Organic Synthesismentioning

confidence: 99%

Commemorating Two Centuries of Iodine Research: An Interdisciplinary Overview of Current Research

et al. 2011

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Iodine was discovered as a novel element in 1811 during the Napoleonic Wars. To celebrate the bicentennial anniversary of this event we reflect on the history and highlight the many facets of iodine research that have evolved since its discovery. Iodine has an impact on many aspects of life on Earth as well as on human civilization. It is accumulated in high concentrations by marine algae, which are the origin of strong iodine fluxes into the coastal atmosphere which influence climatic processes, and dissolved iodine is considered a biophilic element in marine sediments. Iodine is central to thyroid function in vertebrates, with paramount implications for human health. Iodine can exist in a wide range of oxidation states and it features a diverse supramolecular chemistry. Iodine is amenable to several analytical techniques, and iodine compounds have found widespread use in organic synthesis. Elemental iodine is produced on an industrial scale and has found a wide range of applications in innovative materials, including semiconductors--in particular, in solar cells.

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Section: Organic Synthesismentioning

confidence: 99%

Commemorating Two Centuries of Iodine Research: An Interdisciplinary Overview of Current Research

et al. 2011

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“…1), are versatile synthetic transformations with proven applications to the synthesis of biologically relevant molecules (1)(2)(3)(4)(5)(6). The development of catalytic enantioselective halocyclization methods is a topic of increasing interest in synthetic organic chemistry, one that presents unique challenges and opportunities for various paradigms of catalysis in addition to the obvious importance and utility of this transformation.…”

mentioning

confidence: 99%

Lewis base catalysis of bromo- and iodolactonization, and cycloetherification

Denmark

Burk

2010

Proc. Natl. Acad. Sci. U.S.A.

240

140

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Lewis base catalyzed bromo-and iodolactonization reactions have been developed and the effects of catalyst structure on rate and cyclization selectivity have been systematically explored. The effects of substrate structure on halolactonization reactions and the interaction of those effects with the effects of catalyst structure have been investigated, leading to synthetically useful improvements in cyclization selectivity. The knowledge acquired was applied to the development of Lewis base catalyzed bromoand iodocycloetherification reactions. The ability of some of the surveyed catalysts to influence the cyclization selectivity of halolactonization reactions demonstrates their presence in the transition structure of the product-determining cyclization step. This observation implies that chiral derivatives of these catalysts have the potential to provide enantioenriched products regardless of the rates or mechanisms of halonium ion racemization.halocyclofunctionalization | halogenation E lectrophilic halocyclizations of olefins, in which electrophilic halonium ions are generated from olefins and opened intramolecularly by nucleophilic functional groups (Fig. 1), are versatile synthetic transformations with proven applications to the synthesis of biologically relevant molecules (1-6). The development of catalytic enantioselective halocyclization methods is a topic of increasing interest in synthetic organic chemistry, one that presents unique challenges and opportunities for various paradigms of catalysis in addition to the obvious importance and utility of this transformation. To date, only a few notable successes have been reported; these include the use of chiral Ti-salen complexes in iodoetherification (7) and cinchonidinium phasetransfer catalysts in iodolactonization (8). Recently, modified Cinchona alkaloids have been successfully employed in catalytic enantioselective chlorolactonization (9), as well as a catalytic enantioselective bromolactonization of 1,3-eneynes via conjugate opening of achiral bromonium ions (10-15*).Careful mechanistic studies by Brown and coworkers and from these laboratories identified a serious obstacle to the development of catalytic enantioselective iodination and bromination methods, namely the propensity of iodonium and bromonium ions (but not chloronium ions) to undergo degenerate halogen exchange with olefins ( Fig. 2) (16-19). This process racemizes the halonium ions at rates that can compete with nucleophilic capture. Chiral Lewis base catalysts have the potential to prevent this or other racemization processes, if they remain bound to the halonium ion until the newly created stereocenters are irreversibly set, thus maintaining a chiral environment regardless of exchange. Lewis base catalysis of halogenation has been reported in several different contexts (20-23), as have enantioselective halocyclization reactions promoted by stoichiometric amounts of chiral Lewis bases (13-15), but the paucity of catalytic, enantioselective Lewis base catalyzed halogenations suggests that ...

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“…[68] By using this strategy, very recently, Rueping realized the first asymmetric fluorolactonization of a carboxylic acid, [69] in which chiral isobenzofuranon 163 with a fluorinated group was synthesized. However, the reactivity and enantioselectivity were not satisfactory (Scheme 49).…”

Section: Open Cycle Precursors As Substratesmentioning

confidence: 99%

Catalytic Asymmetric Synthesis of Chiral Benzofuranones

Cheng

2014

Adv Synth Catal

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The chiral benzofuranone structural motif is a prominent feature in many natural products, which exhibit a broad range of biological and pharmaceutical activities. In the past few years, a survey of chiral benzofuranone derivatives based on asymmetric catalysis reveals an increasing number of papers, which reflects the latest achievements to facilitate the synthesis of sufficient quantities of related compounds as potential medicinal agents and biological probes. Recent advances in this area are summarized and classified according to the structure of the starting substrate.

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Iodine electrophiles in stereoselective reactions: recent developments and synthetic applications

Cited by 248 publications

References 35 publications

Commemorating Two Centuries of Iodine Research: An Interdisciplinary Overview of Current Research

Commemorating Two Centuries of Iodine Research: An Interdisciplinary Overview of Current Research

Lewis base catalysis of bromo- and iodolactonization, and cycloetherification

Catalytic Asymmetric Synthesis of Chiral Benzofuranones

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