1,2,4-Trifunctionalized Cyclohexane Synthesis via a Diastereoselective Reductive Cope Rearrangement and Functional Group Interconversion Strategy

2021 ◽  
Author(s):  
Michael D. Mannchen ◽  
Ion Ghiviriga ◽  
Khalil A. Abboud ◽  
Alexander J. Grenning
Keyword(s):  
Functional Group ◽  
Cope Rearrangement

scholarly journals Dienamine-Induced Divinylcyclopropane-Cycloheptadiene Rearrangements

2018 ◽  
Author(s):  
Caroline Apel ◽  
Sven Sören Hartmann ◽  
Dieter Lentz ◽  
Mathias Christmann
Keyword(s):  
Secondary Amine ◽  
Functional Group ◽  
High Yield ◽  
Cope Rearrangement ◽  
Cycloaddition Reactions ◽  
Pericyclic Reactions ◽  
Electrocyclic Reactions ◽  
Mild Conditions ◽  
Important Group ◽  
Sigmatropic Rearrangements

Sigmatropic rearrangements constitute an important group of pericyclic reactions. In contrast to cycloaddition reactions, examples of catalytic variants of electrocyclic reactions and sigmatropic rearrangements are still scarce in the chemical literature. Herein, we report the first organocatalytic Cope rearrangement of in situgenerated divinylcyclopropanes. The reactive motif is generated by condensation of 4-(2-vinylcyclopropyl)but-2-enal derivatives and a secondary amine catalyst to form a transient dienamine. The cycloheptadiene products can be obtained in high yield and excellent diastereoselectivity. Importantly, the reaction was demonstrated to be stereospecific, proceeds under mild conditions, and shows broad functional group tolerance. <br>

scholarly journals Dienamine-Induced Divinylcyclopropane-Cycloheptadiene Rearrangements

2018 ◽  
Author(s):  
Caroline Apel ◽  
Sven Sören Hartmann ◽  
Dieter Lentz ◽  
Mathias Christmann
Keyword(s):  
Secondary Amine ◽  
Functional Group ◽  
High Yield ◽  
Cope Rearrangement ◽  
Cycloaddition Reactions ◽  
Pericyclic Reactions ◽  
Electrocyclic Reactions ◽  
Mild Conditions ◽  
Important Group ◽  
Sigmatropic Rearrangements

Sigmatropic rearrangements constitute an important group of pericyclic reactions. In contrast to cycloaddition reactions, examples of catalytic variants of electrocyclic reactions and sigmatropic rearrangements are still scarce in the chemical literature. Herein, we report the first organocatalytic Cope rearrangement of in situgenerated divinylcyclopropanes. The reactive motif is generated by condensation of 4-(2-vinylcyclopropyl)but-2-enal derivatives and a secondary amine catalyst to form a transient dienamine. The cycloheptadiene products can be obtained in high yield and excellent diastereoselectivity. Importantly, the reaction was demonstrated to be stereospecific, proceeds under mild conditions, and shows broad functional group tolerance. <br>

scholarly journals Convergent Synthesis of Trisubstituted Tetrahydrofurans via Bis-Thermally Reactive 1,5-Diene-Tert-Butyl Carbonates.

2019 ◽  
Author(s):  
Alex Grenning ◽  
Fabien Emmetiere
Keyword(s):  
Michael Addition ◽  
Functional Group ◽  
Cascade Reactions ◽  
Cope Rearrangement ◽  
Tandem Reactions ◽  
Convergent Synthesis ◽  
Thermal Reactivity ◽  
Efficient Strategy ◽  
Tert Butyl ◽  
Molecular Complexity

<p>Cascade reactions (also known as domino- or tandem reactions) are an efficient strategy for generating molecular complexity. We report that synergizing the thermal reactivity of 3,3-dicyano-1,5-dienes and <i>tert</i>-butyl carbonates result in stereospecific 2,3,4-trisubstituted tetrahydrofuran synthesis. While substituted tetrahydrofurans can be challenging to synthesize, this discovery converts readily available 1,5-dienes derived from aldehydes, malononitrile, and <i>cis</i>-buten-1,4-diol into complex tetrahydrofurans <i>via </i>a process involving <i>thermal </i>Cope rearrangement, Boc-deprotection, and <i>oxy</i>-Michael addition. Described herein includes background related to the discovery, optimization and scope, and representative functional group interconversion chemistry for the scaffolds. </p>

scholarly journals Convergent Synthesis of Trisubstituted Tetrahydrofurans via Bis-Thermally Reactive 1,5-Diene-Tert-Butyl Carbonates.

2019 ◽  
Author(s):  
Alex Grenning ◽  
Fabien Emmetiere
Keyword(s):  
Michael Addition ◽  
Functional Group ◽  
Cascade Reactions ◽  
Cope Rearrangement ◽  
Tandem Reactions ◽  
Convergent Synthesis ◽  
Thermal Reactivity ◽  
Efficient Strategy ◽  
Tert Butyl ◽  
Molecular Complexity

<p>Cascade reactions (also known as domino- or tandem reactions) are an efficient strategy for generating molecular complexity. We report that synergizing the thermal reactivity of 3,3-dicyano-1,5-dienes and <i>tert</i>-butyl carbonates result in stereospecific 2,3,4-trisubstituted tetrahydrofuran synthesis. While substituted tetrahydrofurans can be challenging to synthesize, this discovery converts readily available 1,5-dienes derived from aldehydes, malononitrile, and <i>cis</i>-buten-1,4-diol into complex tetrahydrofurans <i>via </i>a process involving <i>thermal </i>Cope rearrangement, Boc-deprotection, and <i>oxy</i>-Michael addition. Described herein includes background related to the discovery, optimization and scope, and representative functional group interconversion chemistry for the scaffolds. </p>

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

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>.

Dual Nickel/Palladium-Catalyzed Reductive Cross-Coupling Reactions Between Two Phenol Derivatives

2020 ◽  
Author(s):  
Baojian Xiong ◽  
Yue Li ◽  
Yin Wei ◽  
Søren Kramer ◽  
Zhong Lian
Keyword(s):  
Functional Group ◽  
Low Cost ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Phenol Derivatives ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
One Step ◽  
Aryl Tosylates ◽  
Low Sensitivity

Cross-coupling between substrates that can be easily derived from phenols is highly attractive due to the abundance and low cost of phenols. Here, we report a dual nickel/palladium-catalyzed reductive cross-coupling between aryl tosylates and aryl triflates; both substrates can be accessed in just one step from readily available phenols. The reaction has a broad functional group tolerance and substrate scope (>60 examples). Furthermore, it displays low sensitivity to steric effects demonstrated by the synthesis of a 2,2’disubstituted biaryl and a fully substituted aryl product. The widespread presence of phenols in natural products and pharmaceuticals allow for straightforward late-stage functionalization, illustrated with examples such as Ezetimibe and tyrosine. NMR spectroscopy and DFT calculations indicate that the nickel catalyst is responsible for activating the aryl triflate, while the palladium catalyst preferentially reacts with the aryl tosylate.

Effects of Wet Chemical Oxidation on Surface Functionalization and Morphology of Highly Oriented Pyrolytic Graphite

2020 ◽  
Author(s):  
Mikhail Trought ◽  
Isobel Wentworth ◽  
Timothy Leftwich ◽  
Kathryn Perrine
Keyword(s):  
Surface Functionalization ◽  
Functional Group ◽  
Pyrolytic Graphite ◽  
Surface Oxidation ◽  
Chemical Oxidation ◽  
Synthesis Methods ◽  
Acid Solutions ◽  
Highly Oriented Pyrolytic Graphite ◽  
Wet Chemical ◽  
Surface Morphologies

The knowledge of chemical functionalization for area selective deposition (ASD) is crucial for designing the next generation heterogeneous catalysis. Surface functionalization by oxidation was studied on the surface of highly oriented pyrolytic graphite (HOPG). The HOPG surface was exposed to with various concentrations of two different acids (HCl and HNO3). We show that exposure of the HOPG surface to the acid solutions produce primarily the same -OH functional group and also significant differences the surface topography. Mechanisms are suggested to explain these strikingly different surface morphologies after surface oxidation. This knowledge can be used to for ASD synthesis methods for future graphene-based technologies.

Catalytic Synthesis of Cyclic Guanidines via Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Shunya Ohuchi ◽  
Hiroki Koyama ◽  
Hiroki Shigehisa
Keyword(s):  
Hydrogen Atom ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Catalytic Synthesis ◽  
Membered Ring ◽  
Biologically Active ◽  
Atom Transfer ◽  
Powerful Method ◽  
Protective Groups ◽  
The Common

A catalytic synthesis of cyclic guanidines, which are found in many biologically active compounds and natu-ral products, was developed, wherein transition-metal hydrogen atom transfer and radical-polar crossover were employed. This mild and functional-group tolerant process enabled the cyclization of alkenyl guanidines bearing common protective groups, such as Cbz and Boc. This powerful method not only provided the common 5- and 6-membered rings but also an unusual 7-membered ring. The derivatization of the products afforded various heterocycles. We also investigated the se-lective cyclization of mono-protected or hetero-protected (TFA and Boc) alkenyl guanidines and their further derivatiza-tions.

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