Site-Selective Catalysis of Phenyl Thionoformate Transfer as a Tool for Regioselective Deoxygenation of Polyols

Sánchez‐Roselló, María; Puchlopek, Angela L. A.; Morgan, and Adam J.; Miller, Scott J.

doi:10.1021/jo702334z

Cited by 68 publications

(33 citation statements)

References 58 publications

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“…The selective and direct addressing of different OH groups in important molecules such as carbohydrates or glycopeptide antibiotics (e.g., vancomycin) is a contemporary challenge, and thus nucleophilic organocatalysis seems to be a promising approach in this area. Only a small number of examples of chemo‐ and regioselective acylations of monosacharides and carbohydrates are known (and partially noted in this Review) 92–94. 156 These examples and the impressive desymmetrization by Miller and co‐workers90, 91 (Schemes and ) give hope that, for example, the various OH groups of vancomycin can be selectively addressed directly.…”

Section: Discussionmentioning

confidence: 95%

“…used this approach to show the site‐selective derivatization of erythromycin A by using a tetrapeptide with a proline‐AiB turn 93. The catalytic thionoformate transfer (thionoformate groups can be easily deoxygenated under Barton–McCombie conditions) proved to be more difficult and required the use of additives, for example, FeCl 3 94…”

Section: N‐alkylimidazolesmentioning

confidence: 99%

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Organocatalytic Enantioselective Acyl Transfer onto Racemic as well as meso Alcohols, Amines, and Thiols

2011

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Acyl transfer is at the heart of functional-group transfers utilized both in nature and in the chemical laboratory. Acylations are part of the natural assembly machinery for the generation of complex molecules and for energy transport in biological systems. The recognition of covalent acyl-enzyme intermediates led to both mechanistic studies as well as the development of biomimetic approaches. Consequently, chemists first used the tools of nature in the form of enzymes and naturally occurring alkaloids as catalysts, before eventually developing a large variety of synthetic small molecules for selective acyl transfer. In contrast to nature, chemists utilize acylation reactions as a practical way for stereoselection and functional-group protection. Indeed, the number of studies concerning acyl transfer has significantly increased over the last 15 years. This Review examines and highlights these recent developments with the focus as given in the title.

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Section: Discussionmentioning

confidence: 95%

Section: N‐alkylimidazolesmentioning

confidence: 99%

Organocatalytic Enantioselective Acyl Transfer onto Racemic as well as meso Alcohols, Amines, and Thiols

2011

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“…Bis jetzt gibt es nur eine geringe Zahl an (teilweise in diesem Aufsatz erwähnten) Beispielen für chemo-und regioselektive Acylierungen von Monosachariden und Kohlenhydraten. [92][93][94]156] Diese Beispiele und die beeindruckende Desymmetrisierung von Miller et al [90,91] (Schemata 21 und 22) geben Anlass zur Hoffnung für die direkte, selektive Adressierung z. B. der verschiedenen OH-Gruppen von Vancomycin.…”

Section: Methodsunclassified

Organokatalytischer, enantioselektiver Acyltransfer auf racemische sowie meso‐Alkohole, ‐Amine und ‐Thiole

2011

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Der Acyltransfer ist ein Paradebeispiel für den Transfer funktioneller Gruppen, sowohl in der Natur als auch im chemischen Labor. Acylierungen sind am Aufbau komplexer natürlicher Moleküle beteiligt und spielen eine entscheidende Rolle für den biologischen Energietransport. Die Charakterisierung kovalenter Acyl‐Enzym‐Intermediate trieb sowohl mechanistische Studien als auch die Entwicklung biomimetischer Verfahren an. Folglich verwendeten Chemiker zunächst die Werkzeuge der Natur in Form von Enzymen und natürlichen Alkaloiden als Katalysatoren, um schließlich eine Vielzahl kleiner, synthetischer Moleküle für den selektiven Acyltransfer zu entwickeln. Anders als die Natur nutzen Chemiker praktische Acylierungsreaktionen für die Stereoselektion und zum Schutz funktioneller Gruppen. Die Zahl der Studien zum Acyltransfer hat in den letzten 15 Jahren deutlich zugenommen. Dieser Aufsatz beschreibt diese Entwicklungen mit einem Schwerpunkt auf den im Titel genannten Substanzklassen.

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“…Here, 1,2,2,6,6-pentamethylpiperidine (PEMP) is utilized as a base in tandem with the NMI catalyst. 79 Upon radical cleavage of the C2′–OH, deoxygenated 29 is obtained. The selectivity of the NMI-catalyzed process reveals the inherent reactivity of the C2′ position on 13 , which is overturned when a small peptide catalyst is used.…”

Section: Group Transfer To Hydroxyl Groupsmentioning

confidence: 99%

Applications of Nonenzymatic Catalysts to the Alteration of Natural Products

2017

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The application of small molecules as catalysts for the diversification of natural product scaffolds is reviewed. Specifically, principles that relate to the selectivity challenges intrinsic to complex molecular scaffolds are summarized. The synthesis of analogs of natural products by this approach is then described as a quintessential “late-stage functionalization” exercise wherein natural products serve as the lead scaffolds. Given the historical application of enzymatic catalysts to the site-selective alteration of complex molecules, the focus of this review is on the recent studies of non-enzymatic catalysts. Reactions involving hydroxyl group derivatization with a variety of electrophilic reagents are discussed. C–H bond functionalizations that lead to oxidations, aminations, and halogenations are also presented. Several examples of site-selective olefin functionalizations and C–C bond formations are also included. Numerous classes of natural products have been subjected to these studies of site-selective alteration including polyketides, glycopeptides, terpenoids, macrolides, alkaloids, carbohydrates and others. What emerges is a platform for chemical remodeling of naturally occurring scaffolds that targets virtually all known chemical functionalities and microenvironments. However, challenges for the design of very broad classes of catalysts, with even broader selectivity demands (e.g., stereoselectivity, functional group selectivity, and site-selectivity) persist. Yet, a significant spectrum of powerful, catalytic alterations of complex natural products now exists such that expansion of scope seems inevitable. Several instances of biological activity assays of remodeled natural product derivatives are also presented. These reports may foreshadow further interdisciplinary impacts for catalytic remodeling of natural products, including contributions to SAR development, mode of action studies, and eventually medicinal chemistry.

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Site-Selective Catalysis of Phenyl Thionoformate Transfer as a Tool for Regioselective Deoxygenation of Polyols

Cited by 68 publications

References 58 publications

Organocatalytic Enantioselective Acyl Transfer onto Racemic as well as meso Alcohols, Amines, and Thiols

Organocatalytic Enantioselective Acyl Transfer onto Racemic as well as meso Alcohols, Amines, and Thiols

Organokatalytischer, enantioselektiver Acyltransfer auf racemische sowie meso‐Alkohole, ‐Amine und ‐Thiole

Applications of Nonenzymatic Catalysts to the Alteration of Natural Products

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