scholarly journals Hypervalent Iodine(III)-Mediated Cascade Cyclization of Propargylguanidines and Total Syntheses of Kealiinine B and C

2017 ◽  
Vol 23 (22) ◽  
pp. 5224-5227 ◽  
Author(s):  
Guilong Tian ◽  
Pavel Fedoseev ◽  
Erik V. Van der Eycken
Keyword(s):  
Hypervalent Iodine ◽  
Total Syntheses ◽  
Cascade Cyclization

Enantioselective constructions of quaternary carbons and their application to the asymmetric total syntheses of fredericamycin A and discorhabdin A

2007 ◽  
Vol 79 (4) ◽  
pp. 701-713 ◽  
Author(s):  
Yasuyuki Kita ◽  
Hiromichi Fujioka
Keyword(s):  
Natural Products ◽  
Optically Active ◽  
Biologically Active ◽  
Hypervalent Iodine ◽  
Total Syntheses ◽  
Carbon Centers ◽  
Phenol Derivatives ◽  
Fredericamycin A ◽  
Active Natural ◽  
Quaternary Carbons

An efficient enantioselective construction of quaternary carbons including spiro carbons is an area of intense interest due to the importance of these units as components of biologically active natural products. Prominent methods are presented for the synthesis of chiral, nonracemic quaternary carbon centers by (i) stereospecific rearrangement of optically active epoxides, (ii) enzyme-catalyzed resolution, and (iii) hypervalent iodine reagent-induced ipso-substitution of para-substituted phenol derivatives. These methods were applied to the total syntheses of fredericamycin A and discorhabdin A.

scholarly journals Recent Advances in the Selective Oxidative Dearomatization of Phenols to o-Quinones and o-Quinols with Hypervalent Iodine Reagents

Synlett ◽  
2021 ◽  
Author(s):  
Sarah E. Wengryniuk ◽  
Xiao Xiao
Keyword(s):  
Coordination Chemistry ◽  
Organic Synthesis ◽  
Phenol Oxidation ◽  
Hypervalent Iodine ◽  
Direct Oxidation ◽  
Oxidative Dearomatization ◽  
Total Syntheses ◽  
Recent Advances

Abstract ortho-Quinones are valuable molecular frameworks with diverse applications across biology, materials, organic synthesis, catalysis, and coordination chemistry. Despite their broad utility, their synthesis remains challenging, in particular via the direct oxidation of readily accessible phenols, due to the need to affect regioselective ortho oxidation coupled with the sensitivity of the resulting o-quinone products. The perspective looks at the emergence of I(V) hypervalent iodine reagents as an effective class of oxidants for regioselective o-quinone synthesis. The application of these reagents in regioselective phenol oxidation to both o-quinones and o-quinols will be discussed, including a recent report from our laboratory on the first method for the oxidation of electron-deficient phenols using a novel nitrogen-ligated I(V) reagent. Also included are select examples of total syntheses utilizing this methodology as well as recent advancements in chiral I(V) reagent design for asymmetric phenol dearomatization.1 Introduction2 I(V): Hypervalent Iodine Reagents3 I(V)-Mediated Dearomatization to o-Quinones4 Bisnitrogen-Ligated I(V) Reagents: ortho Dearomatization of Electron-Poor Phenols5 I(V)-Mediated Dearomatization to o-Quinols6 Conclusion and Outlook

Benziodoxole-Derived Organosulfonates: The Strongest Hypervalent Iodine Electrophiles and Oxidants

Synlett ◽  
2019 ◽  
Vol 31 (04) ◽  
pp. 315-326 ◽  
Author(s):  
Viktor V. Zhdankin ◽  
Mekhman S. Yusubov ◽  
Pavel Postnikov ◽  
Akira Yoshimura
Keyword(s):  
Room Temperature ◽  
Trifluoromethanesulfonic Acid ◽  
High Reactivity ◽  
Hypervalent Iodine ◽  
Ionic Character ◽  
Primary Alcohols ◽  
Total Syntheses ◽  
X Ray ◽  
High Yields ◽  
Efficient Reagent

This account describes the development of organosulfonyloxy-substituted iodine(III) and iodine(V) benziodoxole derived reagents, which are thermally stable compounds with useful reactivity patterns. Iodine(III) benziodoxoles and pseudobenziodoxoles are powerful electrophiles and mild oxidants toward various unsaturated compounds. In particular, pseudocyclic benziodoxole-derived triflate (IBA-OTf) is an efficient reagent for oxidative heteroannulation reactions. Aldoximes react with nitriles in the presence of IBA-OTf at room temperature to give 1,2,4-oxadiazoles in high yields. Moreover, IBA-triflate is used as a catalyst in oxidative heteroannulations with m-chloroperoxybenzoic acid as the terminal oxidant. The iodine(V) benziodoxole derived tosylates, DMP-tosylate and IBX-tosylate, are superior oxidants for the oxidation of structurally diverse, synthetically useful alcohols, utilized as key precursors in the total syntheses of polyketide antibiotics and terpenes. And finally, the most powerful hypervalent iodine(V) oxidant, 2-iodoxybenzoic acid ditriflate (IBX·2HOTf), is prepared by treatment of IBX with trifluoromethanesulfonic acid. According to the X-ray data, the I–OTf bonds in IBX-ditriflate have ionic character, leading to the high reactivity of this reagent in various oxidations. In particular, IBX-ditriflate can oxidize polyfluorinated primary alcohols, which are generally extremely resistant to oxidation.1 Introduction2 Iodine(III) Benziodoxole Based Organosulfonates3 Pseudocyclic Iodine(III) Benziodoxole Triflate (IBA-triflate)4 Pseudocyclic Iodine(III) Benziodoxole Tosylates5 Iodine(V) Benziodoxole Derived Tosylates6 Iodine(V) Benziodoxole Derived Triflate (IBX-ditriflate)7 Conclusions

Facile synthesis of 11-aryl-6H-isoindolo[2,1-a]indol-6-ones via hypervalent iodine(iii)-promoted cascade cyclization

RSC Advances ◽  
2015 ◽  
Vol 5 (17) ◽  
pp. 13102-13106 ◽  
Author(s):  
Kapil Dev ◽  
Rakesh Maurya
Keyword(s):  
Efficient Method ◽  
Ring System ◽  
Hypervalent Iodine ◽  
Facile Synthesis ◽  
Metal Free ◽  
Cascade Cyclization

An efficient method was developed for the synthesis of a tetracyclic fused indole and isoindoline ring system, under metal-free conditions.

Total Syntheses of Seven Stemoamide-Type Stemona Alkaloids

2022 ◽  
Author(s):  
Tao Shi ◽  
Fei Cao ◽  
Jin hong Chen ◽  
Xiao-Dong Wang ◽  
Gaofeng Yin ◽  
...  
Keyword(s):  
Total Syntheses ◽  
Transannular Cyclization ◽  
Cascade Cyclization ◽  
The Common ◽  
Stemona Alkaloids

Six Stemona alkaloids were synthesized racemically by using stemoamide, obtained via cascade cyclization or our reported transannular cyclization of parvistemoamide, as the common intermediate. Thioamides facilitated the separation of isosaxorumamide...

Fe-Catalyzed Conjunctive Cross-Couplings of Unactivated Alkenes with Grignard Reagents

2020 ◽  
Author(s):  
Lei Liu ◽  
Wes Lee ◽  
Cassandra R. Youshaw ◽  
Mingbin Yuan ◽  
Michael B. Geherty ◽  
...  
Keyword(s):  
Functional Groups ◽  
Cross Coupling ◽  
Alkyl Halides ◽  
Grignard Reagents ◽  
Turnover Frequency ◽  
Diverse Range ◽  
Cascade Cyclization ◽  
Radical Cascade

The first iron-catalyzed three-component cross-coupling of unactivated olefins with alkyl halides and Grignard reagents is reported. The reaction operates under fast turnover frequency and tolerates a diverse range of sp2-hybridized nucleophiles, alkyl halides, and unactivated olefins bearing diverse functional groups to yield the desired 1,2-alkylarylated products with high regiocontrol. Further, we demonstrate that this protocol is amenable for the synthesis of new (hetero)carbocycles including tetrahydrofurans and pyrrolidines via a three-component radical cascade cyclization/arylation that forges three new C-C bonds.

Oxidase Catalysis via an Aerobically Generated Dess-Martin Periodinane Analogue

2018 ◽  
Author(s):  
Asim Maity ◽  
Sung-Min Hyun ◽  
Alan Wortman ◽  
David Powers
Keyword(s):  
Chemical Synthesis ◽  
Aerobic Oxidation ◽  
Substrate Oxidation ◽  
Oxidation Catalysis ◽  
Hypervalent Iodine ◽  
Oxidation Reactions ◽  
Broad Array ◽  
Oxidation Chemistry ◽  
Reactive Oxidants

<p>Hypervalent iodine(V) reagents, such as Dess-Martin periodinane (DMP) and 2-iodoxybenzoic acid (IBX), are broadly useful oxidants in chemical synthesis. Development of strategies to access these reagents from O2 would immediately enable use of O2 as a terminal oxidant in a broad array of substrate oxidation reactions. Recently we disclosed the aerobic synthesis of I(III) reagents by intercepting reactive oxidants generated during aldehyde autoxidation. Here, we couple aerobic oxidation of iodobenzenes with disproportionation of the initially generated I(III) compounds to generate I(V) reagents. The aerobically generated I(V) reagents exhibit substrate oxidation chemistry analogous to that of DMP. Further, the developed aerobic generation of I(V) has enabled the first application of I(V) intermediates in aerobic oxidation catalysis.</p>

Regioselective C3-H Trifluoromethylation of 2H-Indazole Under Transition-Metal-Free Photoredox Catalysis

2019 ◽  
Author(s):  
Arumugavel Murugan ◽  
Venkata Nagarjuna Babu ◽  
Nagaraj Sabarinathan ◽  
Sharada Duddu. S
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Practical Approach ◽  
Hypervalent Iodine ◽  
Radical Mechanism ◽  
Photoredox Catalysis ◽  
Metal Free

Here we report a visible-light-promoted metal-free regioselective C3-H trifluoromehtylation reaction that proceeds via radical mechanism and which supported by control experiments. The combination of photoredox catalysis and hypervalent iodine reagent provides a practical approach for the present trifluoromethylation reaction and synthesis of a library of trifluoromethylated indazoles.

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