scholarly journals Iron-Catalyzed Halogen Exchange of Trifluoromethyl Arenes

2021 ◽  
Author(s):  
Andreas Dorian ◽  
Emily Landgreen ◽  
Hayley Petras ◽  
James Shepherd ◽  
Florence Williams
Keyword(s):  
Design Of Experiments ◽  
Statistical Method ◽  
Late Stage ◽  
Theoretical Calculations ◽  
Direct Activation ◽  
Aromatic Substrates ◽  
Halogen Exchange ◽  
Iron Coordination

We report the facile production of ArCF<sub>2</sub>X and ArCX<sub>3 </sub>from ArCF<sub>3</sub> using catalytic iron(III)halides, which constitutes the first iron-catalyzed halogen exchange for non-aromatic CF bonds. Theoretical calculations suggest direct activation of C–F bonds by iron coordination. ArCX<sub>3</sub> and ArCF<sub>2</sub>X products of the reaction are synthetically valuable due to their diversification potential. In particular, bromo-, chloro-, and iododifluoromethyl arenes (ArCF<sub>2</sub>Br, ArCF<sub>2</sub>Cl, ArCF<sub>2</sub>I, respectively) provide access to a myriad of difluoromethyl arene derivatives (ArCF<sub>2</sub>R). To optimize for mono-halogen exchange, a statistical method called Design of Experiments was used. Optimized parameters were successfully applied to electron rich and electron deficient aromatic substrates, and to the late stage diversification of flufenoxuron, a commercial insecticide.

scholarly journals Iron-Catalyzed Halogen Exchange of Trifluoromethyl Arenes

2021 ◽  
Author(s):  
Andreas Dorian ◽  
Emily Landgreen ◽  
Hayley Petras ◽  
James Shepherd ◽  
Florence Williams
Keyword(s):  
Design Of Experiments ◽  
Statistical Method ◽  
Late Stage ◽  
Theoretical Calculations ◽  
Direct Activation ◽  
Aromatic Substrates ◽  
Halogen Exchange ◽  
Iron Coordination

We report the facile production of ArCF<sub>2</sub>X and ArCX<sub>3 </sub>from ArCF<sub>3</sub> using catalytic iron(III)halides, which constitutes the first iron-catalyzed halogen exchange for non-aromatic CF bonds. Theoretical calculations suggest direct activation of C–F bonds by iron coordination. ArCX<sub>3</sub> and ArCF<sub>2</sub>X products of the reaction are synthetically valuable due to their diversification potential. In particular, bromo-, chloro-, and iododifluoromethyl arenes (ArCF<sub>2</sub>Br, ArCF<sub>2</sub>Cl, ArCF<sub>2</sub>I, respectively) provide access to a myriad of difluoromethyl arene derivatives (ArCF<sub>2</sub>R). To optimize for mono-halogen exchange, a statistical method called Design of Experiments was used. Optimized parameters were successfully applied to electron rich and electron deficient aromatic substrates, and to the late stage diversification of flufenoxuron, a commercial insecticide.

Supramolecular assembly in metal complexes: Two structural cases

2013 ◽  
Vol 85 (2) ◽  
pp. 397-404 ◽  
Author(s):  
Mohamed Ghazzali
Keyword(s):  
Solid State ◽  
Self Assembly ◽  
Theoretical Calculations ◽  
Supramolecular Assembly ◽  
Halogen Bonding ◽  
One Pot ◽  
Iron Coordination ◽  
Structural Database ◽  
Molecular Components ◽  
Theoretical Analyses

With the current advances in our understanding of molecular components in the solid-state world, the relation between energy and geometry remains controversial. In this study, we deliver a concise account for supramolecular chemistry, and in order to illustrate some of its concepts we describe some structural and theoretical analyses for two unique cases of our work. We elaborate on a supramolecular model of controlled “one-pot” host–guest metal-mediated self-assembly reaction inside iron coordination polymer grid architecture, and we review halogen bonding by specifically observing M–Cl···Cl–M intermolecular interactions using Cambridge Structural Database (CSD) hit analyses with theoretical calculations.

Theoretical Method Research on a MEMS Safety and Arming Device

2014 ◽  
Vol 901 ◽  
pp. 93-97 ◽  
Author(s):  
Fang Yi Liu ◽  
Wen Zhong Lou ◽  
Fu Fu Wang ◽  
Ying Wang
Keyword(s):  
Statistical Method ◽  
Simulation Analysis ◽  
Theoretical Calculations ◽  
Theoretical Method ◽  
Calculation Error ◽  
Spring Stiffness ◽  
Analysis Software ◽  
Element Analysis ◽  
Offset Distance ◽  
Existing Structure

With the intelligent development of small-caliber ammunition, the overall size of the fuze is compressed. In this paper, a theoretical method-energy statistical method has been proposed according to the MEMS S&A device. Taking the slider mass, micro-spring stiffness, latch mechanism size, and initial offset distance into account, the conversion relationship among each part of energy in the process is obtained. For an existing structure of MEMS S&A device, known parameters are utilized to reverse the overload value at arming condition. The ANSYS/LS-DYNA finite element analysis software is used for simulation analysis, thereby confirming the feasibility of theoretical calculations. Also, theoretical calculation error ε is obtained, which to be 0.7%. Energy statistical method and simulation analysis serve as theoretical references for the design of the MEMS S&A device.

scholarly journals Photoinduced regioselective olefination of arenes at proximal and distal sites

2020 ◽  
Author(s):  
Debabrata Maiti ◽  
Argha Saha ◽  
Srimanta Guin ◽  
Wajid Ali ◽  
Trisha Bhattacharya ◽  
...  
Keyword(s):  
Natural Products ◽  
Thermal Energy ◽  
Late Stage ◽  
Traditional Approach ◽  
Theoretical Calculations ◽  
Kinetic Studies ◽  
Multiple Site ◽  
Chiral Molecules ◽  
Silver Salts ◽  
Simultaneous Control

Abstract The Fujiwara-Moritani reaction has had a profound contribution in the emergence of contemporary C-H activation protocols. Despite the applicability of the traditional approach in different fields, the associated reactivity and regioselectivity issues had rendered it redundant. The revival of this exemplary reaction requires the development of a mechanistic paradigm that would have simultaneous control on both the reactivity and regioselectivity. Often high thermal energy required to promote olefination leads to multiple site functionalization. To this aim we established a photoredoxcatalytic system constituting a merger of palladium/organo-photocatalyst that forges oxidative olefination in an explicit regioselective fashion of diverse arenes and heteroarenes. Visible light plays a significant role in executing ‘regio-resolved’ Fuijiwara-Moritani reaction without the requirement of silver salts and thermal energy. The catalytic system is also amenable towards proximal and distal olefination aided by respective directing groups (DGs), which entails the versatility of the protocol in engaging the entire spectrum of C(sp2)-H olefination. Furthermore, streamlining the synthesis of natural products, chiral molecules, drugs and diversification through late-stage functionalizations underscore the importance of this sustainable protocol. The photoinduced attainment of this regioselective transformation is mechanistically established through control reactions, kinetic studies and theoretical calculations.

scholarly journals Visible light mediated photocatalytic [2 + 2] cycloaddition/ring-opening rearomatization cascade of electron-deficient azaarenes and vinylarenes

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Noelia Salaverri ◽  
Rubén Mas-Ballesté ◽  
Leyre Marzo ◽  
José Alemán
Keyword(s):  
Natural Products ◽  
Double Bond ◽  
Visible Light ◽  
Bioactive Compounds ◽  
Late Stage ◽  
Ring Opening ◽  
Functional Group ◽  
Theoretical Calculations ◽  
Double Bonds ◽  
Heterocyclic Derivatives

Abstract The broad presence of azaarene moieties in natural products has promoted the development of new functionalization reactions, giving access to larger libraries of bioactive compounds. The light promoted [2 + 2] photocycloaddition reaction to generate cyclobutanes has been extensively studied in photochemistry. In particular, De Mayo reported the [2 + 2] cycloaddition followed by retroaldol condensation between enols of 1,3-dicarbonyls and double bonds to synthesize 1,5-dicarbonyls. Herein, we describe the [2 + 2] photocycloaddition followed by a ring-opening rearomatization reaction between electron-deficient 2-methylene-azaarenes and double bonds, taking advantage of the ability of these heterocyclic derivatives to form the corresponding pseudo-enamine intermediate. The procedure shows a high functional group tolerance either on the double bond or the heteroarene side and allows the presence of different electron-withdrawing groups. In addition, the wide applicability of this reaction has been demonstrated through the late-stage derivatization of several natural products. Photochemical studies, together with theoretical calculations, support a mechanism involving the photosensitization of the pseudo-enamine intermediate.

scholarly journals Photoinduced Regioselective Olefination of Arenes at Proximal and Distal Sites

2020 ◽  
Author(s):  
Argha Saha ◽  
Srimanta Guin ◽  
Wajid Ali ◽  
Trisha Bhattacharya ◽  
Sheuli Sasmal ◽  
...  
Keyword(s):  
Catalytic System ◽  
Thermal Energy ◽  
Late Stage ◽  
Traditional Approach ◽  
Theoretical Calculations ◽  
Kinetic Studies ◽  
Multiple Site ◽  
Chiral Molecules ◽  
Silver Salts ◽  
Simultaneous Control

The Fujiwara-Moritani reaction has had a profound contribution in the emergence of contemporary C−H activation protocols. Despite the applicability of the traditional approach in different fields, the associated reactivity and regioselectivity issues had rendered it redundant. The revival of this exemplary reaction requires the development of a mechanistic paradigm that would have simultaneous control on both the reactivity and regioselectivity. Often high thermal energy required to promote olefination leads to multiple site functionalization. To this aim we established a photoredox catalytic system constituting a merger of palladium/organo-photocatalyst that forges oxidative olefination in an explicit regioselective fashion of diverse arenes and heteroarenes. Visible light plays a significant role in executing ‘regio-resolved’ Fuijiwara-Moritani reaction without the requirement of silver salts and thermal energy. The catalytic system is also amenable towards proximal and distal olefination aided by respective directing groups (DGs), which entails the versatility of the protocol in engaging the entire spectrum of C(sp<sup>2</sup>)−H olefination. Furthermore, streamlining the synthesis of natural products, chiral molecules, drugs and diversification through late-stage functionalization’s underscore the importance of this sustainable protocol. The photoinduced attainment of this regioselective transformation is mechanistically established through control reactions, kinetic studies and theoretical calculations.

scholarly journals Photoinduced Regioselective Olefination of Arenes at Proximal and Distal Sites

2020 ◽  
Author(s):  
Argha Saha ◽  
Srimanta Guin ◽  
Wajid Ali ◽  
Trisha Bhattacharya ◽  
Sheuli Sasmal ◽  
...  
Keyword(s):  
Catalytic System ◽  
Thermal Energy ◽  
Late Stage ◽  
Traditional Approach ◽  
Theoretical Calculations ◽  
Kinetic Studies ◽  
Multiple Site ◽  
Chiral Molecules ◽  
Silver Salts ◽  
Simultaneous Control

The Fujiwara-Moritani reaction has had a profound contribution in the emergence of contemporary C−H activation protocols. Despite the applicability of the traditional approach in different fields, the associated reactivity and regioselectivity issues had rendered it redundant. The revival of this exemplary reaction requires the development of a mechanistic paradigm that would have simultaneous control on both the reactivity and regioselectivity. Often high thermal energy required to promote olefination leads to multiple site functionalization. To this aim we established a photoredox catalytic system constituting a merger of palladium/organo-photocatalyst that forges oxidative olefination in an explicit regioselective fashion of diverse arenes and heteroarenes. Visible light plays a significant role in executing ‘regio-resolved’ Fuijiwara-Moritani reaction without the requirement of silver salts and thermal energy. The catalytic system is also amenable towards proximal and distal olefination aided by respective directing groups (DGs), which entails the versatility of the protocol in engaging the entire spectrum of C(sp<sup>2</sup>)−H olefination. Furthermore, streamlining the synthesis of natural products, chiral molecules, drugs and diversification through late-stage functionalization’s underscore the importance of this sustainable protocol. The photoinduced attainment of this regioselective transformation is mechanistically established through control reactions, kinetic studies and theoretical calculations.

XUV Absorption Spectra of Carbon Ions

1988 ◽  
Vol 102 ◽  
pp. 71-73
Author(s):  
E. Jannitti ◽  
P. Nicolosi ◽  
G. Tondello
Keyword(s):  
Absorption Spectra ◽  
Cross Section ◽  
Theoretical Calculations ◽  
Photoionization Cross Section ◽  
Carbon Ions

AbstractThe photoabsorption spectra of the carbon ions have been obtained by using two laser-produced plasmas. The photoionization cross-section of the CV has been absolutely measured and the value at threshold, σ=(4.7±0.5) × 10−19cm2, as well as its behaviour at higher energies agrees quite well with the theoretical calculations.

Sign in / Sign up

Export Citation Format

Share Document