Electrochemical Synthesis of Dimeric 2-Oxindole Sharing Vicinal Carbon Quaternary Centers via Proton Coupled Electron Pathway

A metal- and catalyst-free photoinduced radical cascade hydroalkylation of 1,7-enynes has been disclosed. The process is triggered by a SET event involving a photoexcited electron-donor-aceptor complex between NHPI ester and Hantzsch ester, which decomposes to afford a tertiary radical that is readily trapped by the enyne. <a>The method provides an operationally simple, robust and step-economical approach to the construction of diversely functionalized dihydroquinolinones bearing quaternary-centers. A sequential one-pot hydroalkylation-isomerization approach is also allowed giving access to a family of quinolinones. A wide substrate scope and high functional group tolerance was observed in both approaches</a>.

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Diverse Cyclopentenes via Enantioselective Cu-Catalyzed Desymmetrization

10.26434/chemrxiv.6894833.v1 ◽

2018 ◽

Author(s):

Reece Jacques ◽

Robert D. C. Pullin ◽

Stephen P. Fletcher

Keyword(s):

Ring Systems ◽

Quaternary Centers ◽

Stereogenic Centers

<div> <div> <div> <p>A highly regio-, diastereo- and enantioselective Cu-catalyzed desymmetrization of diverse meso-bisphosphates with alkyl zirconium nucleophiles has been developed. The reaction allows access to a broad range of functionalized cyclopentenes with up to three contiguous stereogenic centers, including quaternary centers and spirocyclic ring systems.</p></div></div></div>

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Diverse Cyclopentenes via Enantioselective Cu-Catalyzed Desymmetrization

10.26434/chemrxiv.6894833 ◽

2018 ◽

Author(s):

Reece Jacques ◽

Robert D. C. Pullin ◽

Stephen P. Fletcher

Keyword(s):

Ring Systems ◽

Quaternary Centers ◽

Stereogenic Centers

<div> <div> <div> <p>A highly regio-, diastereo- and enantioselective Cu-catalyzed desymmetrization of diverse meso-bisphosphates with alkyl zirconium nucleophiles has been developed. The reaction allows access to a broad range of functionalized cyclopentenes with up to three contiguous stereogenic centers, including quaternary centers and spirocyclic ring systems.</p></div></div></div>

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Synthesis of Nitrile-Bearing Quaternary Centers via an Equilibrium-Driven Transnitrilation and Anion-Relay Strategy

10.26434/chemrxiv.7834940 ◽

2019 ◽

Author(s):

Sebastien Alazet ◽

Michael West ◽

Purvish Patel ◽

Sophie Rousseaux

Keyword(s):

Building Blocks ◽

One Pot ◽

Quaternary Centers ◽

Synthetic Intermediates

The efficient preparation of nitrile-containing building blocks is of interest due to their utility as synthetic intermediates and their prevalence in pharmaceuticals. As a result, significant efforts have been made to develop methods to access these motifs which rely on safer and non-toxic sources of CN. Herein, we report that 2-methyl-2-phenylpropanenitrile is an efficient, non-toxic, electrophilic CN source for the synthesis of nitrile-bearing quaternary centers via a thermodynamic transnitrilation and anion-relay strategy. This one-pot process leads to nitrile products resulting from the gem-difunctionalization of alkyl lithium reagents.<br>

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