Asymmetric Oxidation of Enol Derivatives to α-Alkoxy Carbonyls Using Iminium Salt Catalysts: A Synthetic and Computational Study

Page, Philip C. Bulman; Almutairi, Saud M.; Chan, Yohan; Stephenson, G. R.; Gama, Yannick; Goodyear, Ross L.; Douteau, Alice; Allin, Steven M.; Jones, G.

doi:10.1021/acs.joc.8b02354

Cited by 9 publications

(5 citation statements)

References 107 publications

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“…This oxaziridinium formation is thought to be diastereoselective. [25] Nucleophilic attack on the oxaziridinium by the phenolate gives rise to the o-quinol, in the enantiodetermining step of the reaction. The o-quinol then dimerizes in a regio-and diastereoselective manner, [26] giving rise to the bicyclo[2.2.2]octenone product.…”

Section: Methodsmentioning

confidence: 99%

Organocatalytic Enantioselective Synthesis of Bicyclo[2.2.2]octenones via Oxaziridinium Catalysed ortho‐Hydroxylative Phenol Dearomatization**

2022

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Hydroxylative dearomatization reactions of phenols (HPD) offer an efficient way to assemble complex, biologically relevant scaffolds. Despite this, enantioselective hydroxylative phenol dearomatizations for the construction of bicyclo[2.2.2]octenones are classically limited to stoichiometric chiral reagents, and a practical, enantioselective catalytic method has remained elusive. Herein, we describe a highly enantioselective, organocatalytic tandem o‐HPD‐[4+2] reaction. Our methodology utilizes a chiral oxaziridinium organocatalyst, that is available in both enantiomeric forms, to afford dearomatized products in high enantioselectivity over a range of phenol substitution patterns. This approach was applied to the highly enantioselective synthesis of (+)‐biscarvacrol (99 : 1 e.r.) and (−)‐bis(2,6‐xylenol) (94 : 6 e.r.). The practicality of our conditions was demonstrated at gram‐scale, using an amine precatalyst, accessible in a single synthetic step.

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Section: Methodsmentioning

confidence: 99%

Organocatalytic Enantioselective Synthesis of Bicyclo[2.2.2]octenones via Oxaziridinium Catalysed ortho‐Hydroxylative Phenol Dearomatization**

2022

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“…In a related study, Jones and co-workers explored the epoxidation and hydroxylation of cyclic vinyl phosphate acetate and trialkylsilyl ethers. They observed that vinyl phosphate and trialkylsilyl ethers performed significantly worse than the corresponding vinyl acetate [ 214 ].…”

Section: Oxidation and Reduction Reactions Of Organophosphatesmentioning

confidence: 99%

Organophosphates as Versatile Substrates in Organic Synthesis

Oeser,

Tobrman

2024

Molecules

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This review summarizes the applications of organophosphates in organic synthesis. After a brief introduction, it discusses cross-coupling reactions, including both transition-metal-catalyzed and transition-metal-free substitution reactions. Subsequently, oxidation and reduction reactions are described. In addition, this review highlights the applications of organophosphates in the synthesis of natural compounds, demonstrating their versatility and importance in modern synthetic chemistry.

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“…The authors have cited additional references within the Supporting Information. [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51]…”

Section: Supporting Informationmentioning

confidence: 99%

Stabilization of sp‐Hybridized Nitrogen Cation by Lewis Acid‐Base Complex Formation with Intramolecular Iodine

Fujino,

Hyodo,

Otani

et al. 2023

Chemistry A European J

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Here we show that the sp‐hybridized nitrogen cation is strongly stabilized by a peri‐iodine substituent in the tetralone system. The cation is captured by anionic species such as CF3CO2−, affording hypervalent iodine(III) compounds with a short nitrogen‐iodine (N−I) bond, in which the cation serves as a Lewis acid. Notably, the O−I bond of the O‐trifluoroacetate or O‐acetate is intrinsically weaker than the N−I bond due to its more ionic character and is further weakened by protonation in trifluoroacetic acid. As a result, the oxygen ligand can dissociate in the presence of a Brønsted acid, affording a I+ cation intermediate that retains the N−I bond. We isolated the cation as the tetrafluoroborate, and characterized it experimentally by 1H NMR spectroscopy and X‐ray structure analysis, and theoretically by means of DFT calculation. The results suggest that the N−I bonded cation is intrinsically stable, and is weakly coordinated with water and the BF4 counter anion or trifluoroacetate anion. This cation can be employed as a reagent for α‐oxidation of ketones.

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Asymmetric Oxidation of Enol Derivatives to α-Alkoxy Carbonyls Using Iminium Salt Catalysts: A Synthetic and Computational Study

Cited by 9 publications

References 107 publications

Organocatalytic Enantioselective Synthesis of Bicyclo[2.2.2]octenones via Oxaziridinium Catalysed ortho‐Hydroxylative Phenol Dearomatization**

Organocatalytic Enantioselective Synthesis of Bicyclo[2.2.2]octenones via Oxaziridinium Catalysed ortho‐Hydroxylative Phenol Dearomatization**

Organophosphates as Versatile Substrates in Organic Synthesis

Stabilization of sp‐Hybridized Nitrogen Cation by Lewis Acid‐Base Complex Formation with Intramolecular Iodine

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