ChemInform Abstract: Facile and Highly Diastereoselective Synthesis of syn‐ and cis‐1,2‐Diol Derivatives from Protected α‐Hydroxy Ketones.

Jahn, Emanuela; Smrček, Jakub; Pohl, Radek; Cı́sařová, Ivana; Jones, Peter G.; Jahn, Ullrich

doi:10.1002/chin.201617042

Cited by 2 publications

(2 citation statements)

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“…Hydroxyimino ester 32a was isolated as a 1:1 diastereomeric mixture, likely caused by epimerization at C2 of menthone. 35 The isomeric thermodynamic silyl enol ether 31c afforded in contrast 59% of opened oxime ester 32b together with 16% of 32a.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Enolate-Based Regioselective Anti-Beckmann C–C Bond Cleavage of Ketones

Mašek

Jahn

2021

J. Org. Chem.

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The Baeyer–Villiger or Beckmann rearrangements are established methods for the cleavage of ketone derivatives under acidic conditions, proceeding for unsymmetrical precursors selectively at the more substituted site. However, the fragmentation regioselectivity cannot be switched and fragmentation at the less-substituted terminus is so far not possible. We report here that the reaction of ketone enolates with commercial alkyl nitrites provides a direct and regioselective way of fragmenting ketones into esters and oximes or ω-hydroxyimino esters, respectively. A comprehensive study of the scope of this reaction with respect to ketone classes and alkyl nitrites is presented. Control over the site of cleavage is gained through regioselective enolate formation by various bases. Oxidation of kinetic enolates of unsymmetrical ketones leads to the otherwise unavailable “anti-Beckmann” cleavage at the less-substituted side chain, while cleavage of thermodynamic enolates of the same ketones represents an alternative to the Baeyer–Villiger oxidation or the Beckmann rearrangement under basic conditions. The method is suited for the transformation of natural products and enables access to orthogonally reactive dicarbonyl compounds.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Enolate-Based Regioselective Anti-Beckmann C–C Bond Cleavage of Ketones

Mašek

Jahn

2021

J. Org. Chem.

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“…The treatment of 3c with L-selectride produced a cyclohexanol 7a as the major product with excellent enantio-and diastereoseletivities. 18 The removal of the directing group by Ni-catalyzed alcoholysis 19 provided a carboxylic ester 8 in a 94% yield and with maintained optical purity.…”

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confidence: 99%

Enantioselective Addition of Cyclic Ketones to Unactivated Alkenes Enabled by Amine/Pd(II) Cooperative Catalysis

et al. 2018

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Amine/Pd(II) cooperative catalysis has enabled a highly enantioselective addition of cyclic ketones to unactivated alkenes. The hallmark of the strategy includes amide-directed, regioselective activation of alkenes by Pd(II) and enhancing the nucleophilicity of α-carbon of the ketones by enamine catalysis to synergistically drive the reaction, which is basically unable to be accessed by a single catalyst. The combination of a commercially available Pd(II) catalyst and diphenylprolinol was able to provide the γ-addition products with good to high yields and efficient stereochemical control (up to 95% ee).

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ChemInform Abstract: Facile and Highly Diastereoselective Synthesis of syn‐ and cis‐1,2‐Diol Derivatives from Protected α‐Hydroxy Ketones.

Cited by 2 publications

References 1 publication

Enolate-Based Regioselective Anti-Beckmann C–C Bond Cleavage of Ketones

Enolate-Based Regioselective Anti-Beckmann C–C Bond Cleavage of Ketones

Enantioselective Addition of Cyclic Ketones to Unactivated Alkenes Enabled by Amine/Pd(II) Cooperative Catalysis

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