Metal-Mediated Oxidation of Tertiary Alcohols and Related Fragmentations

Wietzerbin, Karine; Bernadou, Jean; Meunier, Bernard

doi:10.1002/1099-0682(200007)2000:7<1391::aid-ejic1391>3.0.co;2-c

Cited by 26 publications

(27 citation statements)

References 60 publications

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“…Initial attempts to effect oxidative fragmentation (20, 24) of C11–C19 bond were met with failure and though iodide 9 could be obtained in excellent yield by the use of Barluenga’s reagent (25), the cost of the reagent proved to be a substantial drawback for large-scale operations. A more economical alternative was finally realized by employing N-iodosuccinimide as oxidant (26).…”

mentioning

confidence: 99%

Strategic Redox Relay Enables A Scalable Synthesis of Ouabagenin, A Bioactive Cardenolide

Renata

Zhou

Baran

2013

Science

162

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Here we report a scalable route to the polyhydroxylated steroid ouabagenin with an unusual spin on the age-old practice of steroid semi-synthesis. The incorporation of both redox and stereochemical relays during the design of this synthesis resulted in efficient access to more than 500 mg of a key precursor towards ouabagenin–and ultimately ouabagenin itself–and the discovery of innovative methods for C–H and C–C activation and C–O bond hemolysis. Given the medicinal relevance of the cardenolides in the treatment of congestive heart failure, a variety of ouabagenin analogs could potentially be generated from the key intermediate as a means of addressing the narrow therapeutic index of these molecules.

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mentioning

confidence: 99%

Strategic Redox Relay Enables A Scalable Synthesis of Ouabagenin, A Bioactive Cardenolide

Renata

Zhou

Baran

2013

Science

162

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“…Wirz eigen unerwartete und neue photokatalytische Reaktionen dieser Alkohole,die ein generelles mechanistisches Verständnis ermçglichen. [2,16] Deshalb wäre das Abstoßen eines Radikals und die einhergehende stçchiometrische Produktion von H 2 in Analogie zur tert-Butanol-Photoreformierung zu erwarten. Zum Beispiel ermçglicht sie die Aufklärung des Verhaltens von Alkylradikalen auf Oberflächen, was wichtig fürd ie Photo-Kolbe-Reaktion [13] und die Fischer-Tropsch-Synthese [14] ist.…”

Section: Die Selektive Oxidation Von Alkoholen Zu Aldehyden Undunclassified

Reaktionswege in der photokatalytischen Umsetzung tertiärer Alkohole auf Rutil‐TiO₂(110)

et al. 2019

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Laut Lehrbüchern sind tertiäre Alkohole inert gegenüber Oxidationen. Die Photokatalyse tertiärer Alkohole auf einem Titandioxideinkristall unter definierten Vakuumbedingungen offenbart unerwartete und neue Reaktionen, die Disproportionierung in ein Alkan und das entsprechende Keton. Im Gegensatz zu primären und sekundären Alkoholen führt die Abwesenheit eines a-H zu einem C À C-Bindungsbruch statt der üblichen Wasserstoffabspaltung.D ie Bindung zu einer Methylgruppe wird nichtg espalten, wenn sich im Alkohol eine hçhere Alkankette in a-Stellung zur Hydroxylgruppe befindet. Eine Platinbeladung erhçht nicht nur die Reaktionsrate,sondern ermçglicht einen neuen Reaktionsweg: die Bildung molekularen Wasserstoffs und eines langkettigen Alkans,d as sich durch Rekombination zweier Alkylspezies bildet. Diese Arbeit zeigt, dass neue synthetische Routen durch Einführungen photokatalytischer Reaktionsschritte mçglich gemacht werden, in denen der Cokatalysator eine entscheidende Rolle spielt.

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“…In contrast, Cr(VI) oxidations of the C@C moiety of alkenes have been less useful in that these reactions typically result in product mixtures containing diols, halohydrins and epoxides [1]. The mechanism of such alkene oxidations and the nature of the transition state have been thoroughly investigated and still remain controversial [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…This process has recently been used in the synthesis of polyether natural products [7,8]. Three different mechanisms have been proposed as illustrated in Figure 2: (2 + 2) or (3 + 2) cycloaddition processes and Cr(VI)-mediated epoxidation [3,6,9]. However, like the intermolecular alkene oxidations discussed above, the mechanism of this intramolecular process has not been established.…”

Section: Introductionmentioning

confidence: 99%

Pyridinium chlorochromate (PCC) oxidation of bishomoallylic tertiary alcohols. A structure–reactivity study

Beihoffer

Craven

Knight

et al. 2005

Transition Met Chem

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The mechanism of the Cr(VI) oxidation of an alkene C@C is not known for certain. A particularly useful and novel example of this process is the intramolecular oxidative cyclization of bishomoallylic tertiary alcohols by pyridinium chlorochromate (PCC) to yield substituted tetrahydrofuran products via the tethered chromate ester. Several such tertiary alcohols were prepared in this study which varied in the number and position of alkyl groups attached to the C@C. The relative reactivity of these substrates toward PCC under standard conditions is dependent only on the number of R groups on the C@C, not on the degree of substitution on the most highly substituted alkene carbon. This observation suggests a symmetrical transition state in this intramolecular Cr(VI) alkene oxidation.

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Metal-Mediated Oxidation of Tertiary Alcohols and Related Fragmentations

Cited by 26 publications

References 60 publications

Strategic Redox Relay Enables A Scalable Synthesis of Ouabagenin, A Bioactive Cardenolide

Strategic Redox Relay Enables A Scalable Synthesis of Ouabagenin, A Bioactive Cardenolide

Reaktionswege in der photokatalytischen Umsetzung tertiärer Alkohole auf Rutil‐TiO₂(110)

Pyridinium chlorochromate (PCC) oxidation of bishomoallylic tertiary alcohols. A structure–reactivity study

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Metal-Mediated Oxidation of Tertiary Alcohols and Related Fragmentations

Cited by 26 publications

References 60 publications

Strategic Redox Relay Enables A Scalable Synthesis of Ouabagenin, A Bioactive Cardenolide

Strategic Redox Relay Enables A Scalable Synthesis of Ouabagenin, A Bioactive Cardenolide

Reaktionswege in der photokatalytischen Umsetzung tertiärer Alkohole auf Rutil‐TiO2(110)

Pyridinium chlorochromate (PCC) oxidation of bishomoallylic tertiary alcohols. A structure–reactivity study

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Reaktionswege in der photokatalytischen Umsetzung tertiärer Alkohole auf Rutil‐TiO₂(110)