Direct α-acyloxylation of organic sulfides with the hypervalent (diacyloxyiodo)benzene/tetra-n-butylammonium bromide (TBAB) reagent combination

Zhu, Donghui; Chang, Dong Chil; Gan, Shaoyan; Shi, Lei

doi:10.1039/c6ra01799a

Cited by 14 publications

(4 citation statements)

References 67 publications

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“…The all-cis configuration in 34a and 34b was proven by NOESY-spectroscopy. Similar αoxidations of sulfides by hypervalent iodine species have been reported previously [33][34][35][36][37] , but only in the presence of a metal catalyst. Attempts to reduce the thioacetal groups with Et3SiH/TFA at low temperature gave 32 in very low yields only (9-11%) (see Table S1 for screening conditions).…”

Section: Synthesis Of Zampanolide Analogs 4-8supporting

confidence: 82%

Synthesis and Structure-Activity Relationship Studies of Dioxane- and Oxathiane-Based Analogs of (–)-Zampanolide

Cotter,

Glauser,

Lelke

et al. 2024

Preprint

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We have prepared a series of analogs of the complex marine macrolide (–)-zampanolide, which incorporate a dioxane-, oxathiane-, or oxathiane-dioxide ring in place of the natural tetrahydropyran moiety and we have determined their microtubule-binding affinity and antiproliferative activity against human cancer cells. The synthesis of these analogs was based on a convergent strategy with a HWE-based macrocyclization and a stereoselective aza-aldol reaction as key steps. The microtubule-binding affinity and cellular potency of the dioxane- and oxathiane-based analogs with a natural (Z,E)-sorbamide-based side chain were essentially indistinguishable from those of natural (–)-zampanolide; changing the configuration of the sorbamide unit from Z,E to E,E resulted in a slight loss in activity. In contrast, the presence of an oxathiane-dioxide ring caused a steep decrease in microtubule-binding and a significant loss in growth inhibitory activity. In addition, a substantial loss in potency was observed against a multidrug-resistant, P-glycoprotein-overexpressing cell line, while no such effect was found for the dioxane- or oxathiane-based analogs. A high-resolution X-ray crystal structure of the complex between beta-tubulin and dioxane-zampanolide was obtained, which showed that this compound, like natural (–)-zampanolide, induces helical structuring of the M-loop.

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Section: Synthesis Of Zampanolide Analogs 4-8supporting

confidence: 82%

Synthesis and Structure-Activity Relationship Studies of Dioxane- and Oxathiane-Based Analogs of (–)-Zampanolide

Cotter,

Glauser,

Lelke

et al. 2024

Preprint

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“…For the previously reported sulfonium salt-mediated approach (entry 1, method i), the unwanted sulfur oxidation reaction predominated over sulfilimine formation. Interestingly, in the absence of cyanonitrene, the Pummerer rearrangement products 2d , 2e , and sulfoxide 2c were obtained in low yields (entry 2, method ii). In contrast to the sulfonium salt electrophile, the thionium ion only generated a small quantity of sulfoxide 2c after the H 2 O workup (entry 1 vs 2).…”

Section: Resultsmentioning

confidence: 99%

Selective Synthesis of N-Cyano Sulfilimines by Dearomatizing Stable Thionium Ions

et al. 2020

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For the selective synthesis of N-cyano sulfilimines, we have developed a new method based on the soft−soft interaction between thionium ion electrophiles and cyanonitrene nucleophiles. The stable thionium ion was successfully obtained by oxidative dearomatization using phenyliodine (III) diacetate (PIDA) in N,N-dimethylformamide (DMF). The sulfur imination reactions were tolerant to a wide range of functional groups and exhibited high selectivities and excellent yields. The existence of thionium ion intermediates was confirmed by ultraviolet/visible (UV/vis) spectroscopy and 1 H NMR experiments.

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“…Shi with coworkers reported a metal‐free synthetic procedure that allowed preparing α ‐acyloxy sulfides 184 from alkyl sulfides of the type 183 using only PhI(OCOR) oxidant in combination with TBAB under mild reaction conditions (room temperature) in DCM. [ 119 ] The yields varied from good to excellent (Scheme 31). Apparently, the high process selectivity might be ascribed to the generation of highly active intermediate tetra ‐n ‐butylammonium [di(acyloxy)bromate], responsible for α ‐acyloxylation and suppression of the competitive undesired substrate sulfoxidation.…”

Section: Metal‐free Acyloxylationsmentioning

confidence: 99%

Recent progress in catalytic acyloxylation of C(sp³)‐H bonds

Antonov

Bryliakov

2022

Applied Organom Chemis

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Herewith, recent progress in the transition metal catalyzed, as well as metal‐free and electrochemical selective acyloxylations of C(sp3)‐H bonds is surveyed. The corresponding modifications of different substrate types such as amines, amides, oximes, aminoacids, nitrogen‐containing heterocycles, olefins, carbonyl compounds, carboxylic acids, and acetals are covered, focusing on their synthetic potential. Correlations between the nature of the catalyst, oxidant, additives, conditions, and the acyloxylation regio‐ and chemoselectivity, are revealed, and available mechanistic details are discussed briefly. The time span of the review is 2015 to present time.

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Direct α-acyloxylation of organic sulfides with the hypervalent (diacyloxyiodo)benzene/tetra-n-butylammonium bromide (TBAB) reagent combination

Abstract: A novel metal-free approach to directly synthesize α-acyloxy sulfides from readily available alkyl sulfides utilizing hypervalent (diacyloxyiodo)benzene and TBAB reagent combination was developed.

Cited by 14 publications

References 67 publications

Synthesis and Structure-Activity Relationship Studies of Dioxane- and Oxathiane-Based Analogs of (–)-Zampanolide

Synthesis and Structure-Activity Relationship Studies of Dioxane- and Oxathiane-Based Analogs of (–)-Zampanolide

Selective Synthesis of N-Cyano Sulfilimines by Dearomatizing Stable Thionium Ions

Recent progress in catalytic acyloxylation of C(sp³)‐H bonds

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Direct α-acyloxylation of organic sulfides with the hypervalent (diacyloxyiodo)benzene/tetra-n-butylammonium bromide (TBAB) reagent combination

Abstract: A novel metal-free approach to directly synthesize α-acyloxy sulfides from readily available alkyl sulfides utilizing hypervalent (diacyloxyiodo)benzene and TBAB reagent combination was developed.

Cited by 14 publications

References 67 publications

Synthesis and Structure-Activity Relationship Studies of Dioxane- and Oxathiane-Based Analogs of (–)-Zampanolide

Synthesis and Structure-Activity Relationship Studies of Dioxane- and Oxathiane-Based Analogs of (–)-Zampanolide

Selective Synthesis of N-Cyano Sulfilimines by Dearomatizing Stable Thionium Ions

Recent progress in catalytic acyloxylation of C(sp3)‐H bonds

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Recent progress in catalytic acyloxylation of C(sp³)‐H bonds