Gold-catalyzed construction of two adjacent quaternary stereocenters via sequential C–H functionalization and aldol annulation

Development of a new synthetic method for the construction of quaternary centers with a CF3 group was realized by way of 1,6-addition of various nucleophiles to highly reactive δ-trifluoromethylated p-quinone methides generated in situ.

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Asymmetric Synthesis of Spirooxindole δ-Lactones with Vicinal Tertiary and Quaternary Stereocenters via Regio-, Diastereo-, and Enantioselective Organocatalytic Vinylogous Aldol-cyclization Cascade Reaction

Advanced Synthesis & Catalysis ◽

10.1002/adsc.201701104 ◽

2017 ◽

Vol 359 (22) ◽

pp. 4043-4049 ◽

Cited By ~ 16

Author(s):

Jeng-Liang Han ◽

You-Da Tsai ◽

Chia-Hao Chang

Keyword(s):

Asymmetric Synthesis ◽

Cascade Reaction ◽

Aldol Cyclization ◽

Quaternary Stereocenters

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Intermolecular Stereoselective Iridium-Catalyzed Allylic Alkylation: An Evolutionary Account

Synlett ◽

10.1055/s-0037-1610217 ◽

2018 ◽

Vol 29 (19) ◽

pp. 2481-2492 ◽

Cited By ~ 26

Author(s):

Brian Stoltz ◽

Samantha Shockley ◽

J. Hethcox

Keyword(s):

Palladium Catalysts ◽

Allylic Alkylation ◽

Direct Construction ◽

Iridium Catalysts ◽

Quaternary Centers ◽

Evolutionary Account ◽

Palladium Catalyzed ◽

Quaternary Stereocenters ◽

Quaternary Stereocenter ◽

Alkylation Reactions

Our lab has long been interested in the development of methods for the creation of enantioenriched all-carbon quaternary stereocenters. Historically, our interest has centered on palladium-catalyzed allylic alkylation, though recent efforts have moved to include the study of iridium catalysts. Whereas palladium catalysts enable the preparation of isolated stereocenters, the use of iridium catalysts allows for the direct construction of vicinal stereocenters via an enantio-, diastereo-, and regioselective allylic alkylation. This Account details the evolution of our research program from inception, which focused on the first iridium-catalyzed allylic alkylation to prepare stereodyads containing a single quaternary stereocenter, to our most recent discovery that allows for the synthesis of vicinal quaternary centers.1 Introduction2 Synthesis of Vicinal Tertiary and All-Carbon Quaternary Stereocenters via Enantio- and Diastereoselective Iridium-Catalyzed Allylic Alkylation2.1 Cyclic Nucleophiles2.2 Acyclic Nucleophiles2.3 Alkyl-Substituted Electrophiles3 Umpoled Iridium-Catalyzed Allylic Alkylation Reactions3.1 Tertiary Allylic Stereocenters3.2 Quaternary Allylic Stereocenters4 Synthesis of Vicinal All-Carbon Quaternary Centers via Enantioselective Iridium-Catalyzed Allylic Alkylation5 Summary and Future Outlook

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Five‐Step Synthesis of Yaequinolones J1 and J2

10.26434/chemrxiv.11359553.v1 ◽

2019 ◽

Author(s):

Johannes Schwan ◽

Merlin Kleoff ◽

Philipp Heretsch ◽

Mathias Christmann

Keyword(s):

Bond Forming ◽

Aldol Cyclization

A concise synthesis of yaequinolones J1 and J2 is reported. The route is based on the aryne insertion into the σ- C–N-bond of an unsymmetric imide followed by a diastereoselective aldol cyclization of the resulting N-acylated aminobenzophenone. The chromene motif is generated in the first step by an organocatalytic tandem Knoevenagel-electrocyclization of citral and 2-bromoresorcinol. The approach adheres to the ideality-principle, using almost exclusively strategic bond-forming<br>reactions.

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Metal-Free Photoinduced Hydroalkylation Cascade Enabled by an Electron-Donor-Acceptor Complex

10.26434/chemrxiv.11912073 ◽

2020 ◽

Author(s):

José Tiago Menezes Correia ◽

Gustavo Piva da Silva ◽

Camila Menezes Kisukuri ◽

Elias André ◽

Bruno Pires ◽

...

Keyword(s):

Electron Donor ◽

Functional Group ◽

Photoexcited Electron ◽

One Pot ◽

Quaternary Centers ◽

Metal Free ◽

Acceptor Complex ◽

Catalyst Free ◽

Donor Acceptor ◽

Radical Cascade

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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