scholarly journals Isomeric triazines exhibit unique profiles of bioorthogonal reactivity

2019 ◽  
Vol 10 (39) ◽  
pp. 9109-9114 ◽  
Author(s):  
David N. Kamber ◽  
Sean S. Nguyen ◽  
Fang Liu ◽  
Jeffrey S. Briggs ◽  
Hui-Wen Shih ◽  
...  
Keyword(s):  
Unique Reaction ◽  
Strained Alkenes

Isomeric triazines can be tuned to exhibit unique reaction profiles with biocompatible strained alkenes and alkynes.

Potassium Arylethynyltrifluoroborate as an Unstrained Dienophile for Ultrafast and On Demand Activation of Bioorthogonal IEDDA Reactions

2019 ◽  
Author(s):  
Zijian Guo ◽  
Bruno Oliveira ◽  
Claudio D. Navo ◽  
Pedro M. S. D. Cal ◽  
Francisco Corzana ◽  
...  
Keyword(s):  
Protein Modification ◽  
Cross Reactivity ◽  
Diels Alder ◽  
Inverse Electron Demand ◽  
On Demand ◽  
Strained Alkenes ◽  
Electron Demand

<p>Strained alkenes and alkynes are the predominant dienophiles used in inverse electron-demand Diels-Alder (IEDDA) reactions, however, their instability, cross-reactivity and accessibility are problematic. Unstrained dienophiles, although physiologically stable and synthetically accessible, react with tetrazines significantly slower relative to strained variants. Here we report the development of potassium arylethynyltrifluoroborates as unstrained dienophiles for ultrafast, chemically triggered IEDDA reactions. By varying the substituents on the tetrazine (e.g. pyridyl- to benzyl-substituents), cycloaddition rates can vary from nearly spontaneous (<i>t</i><sub>1/2</sub>≈ 9 s) to no reaction with the unstrained alkyne-BF3 dienophile. The reported system was applied to protein modification and enabled mutually orthogonal labelling of two distinct proteins.</p>

Potassium Arylethynyltrifluoroborate as an Unstrained Dienophile for Ultrafast and On Demand Activation of Bioorthogonal IEDDA Reactions

2019 ◽  
Author(s):  
Zijian Guo ◽  
Bruno Oliveira ◽  
Claudio D. Navo ◽  
Pedro M. S. D. Cal ◽  
Francisco Corzana ◽  
...  
Keyword(s):  
Protein Modification ◽  
Cross Reactivity ◽  
Diels Alder ◽  
Inverse Electron Demand ◽  
On Demand ◽  
Strained Alkenes ◽  
Electron Demand

<p>Strained alkenes and alkynes are the predominant dienophiles used in inverse electron-demand Diels-Alder (IEDDA) reactions, however, their instability, cross-reactivity and accessibility are problematic. Unstrained dienophiles, although physiologically stable and synthetically accessible, react with tetrazines significantly slower relative to strained variants. Here we report the development of potassium arylethynyltrifluoroborates as unstrained dienophiles for ultrafast, chemically triggered IEDDA reactions. By varying the substituents on the tetrazine (e.g. pyridyl- to benzyl-substituents), cycloaddition rates can vary from nearly spontaneous (<i>t</i><sub>1/2</sub>≈ 9 s) to no reaction with the unstrained alkyne-BF3 dienophile. The reported system was applied to protein modification and enabled mutually orthogonal labelling of two distinct proteins.</p>

Stereoretentive Olefin Metathesis: A New Avenue for the Synthesis of All-cis Poly(p-phenylene vinylene)s and Stereo­defined Polyalkenamers

Synlett ◽  
2021 ◽  
Author(s):  
Quentin Michaudel ◽  
Samuel J. Kempel ◽  
Ting-Wei Hsu
Keyword(s):  
Olefin Metathesis ◽  
Ring Opening ◽  
Diblock Copolymers ◽  
Catalyst Design ◽  
Phenylene Vinylene ◽  
Grand Challenge ◽  
Ru Catalyst ◽  
Unique Reaction ◽  
Photochemical Isomerization ◽  
Optimized Conditions

AbstractOlefin metathesis has tremendously impacted all fields of synthetic chemistry. However, the control of the olefin stereochemistry during this process remains a grand challenge. Recent innovations in catalyst design have permitted control of the stereochemistry of the olefin product. Here, we discuss the development of stereoretentive olefin metathesis, with an emphasis on the synthesis of stereodefined polyalkenamers through ring-opening metathesis polymerization (ROMP). We then present our application of this unique reaction manifold to the preparation of all-cis poly(p-phenylene vinylene)s (PPVs). A dithiolate Ru catalyst was found to deliver perfect cis selectivity for the polymerization of a paracyclophane diene monomer. By using optimized conditions, all-cis PPVs with narrow dispersities and predictable molar masses were obtained by varying the ratio of monomer to catalyst. The high chain fidelity of the stereoretentive ROMP with a paracyclophane diene monomer enabled the preparation of well-defined diblock copolymers with a norbornene co-monomer. Photochemical isomerization of all-cis to all-trans PPVs was effected with both homopolymers and diblock copolymers. This process was shown to be selective for the PPV block, and resulted in changes in optical properties, polymer size, and solubility. Stereoretentive ROMP provides a promising platform for synthesizing polymers with unique properties, including photoresponsive all-cis PPVs with living characteristics.1 Introduction2 Synthetic Applications of Stereoretentive Olefin Metathesis3 Stereocontrol of Polyalkenamers through Stereoretentive ROMP4 Stereoretentive ROMP To Access All-cis Poly(p-phenylene vinylene)s5 Conclusion

Palladium-Catalyzed Annulation of Aryl Heterocycles with Strained Alkenes

2007 ◽  
Vol 9 (9) ◽  
pp. 1761-1764 ◽  
Author(s):  
David G. Hulcoop ◽  
Mark Lautens
Keyword(s):  
Palladium Catalyzed ◽  
Strained Alkenes

scholarly journals Diazo group as a new chemical reporter for bioorthogonal labelling of biomolecules

RSC Advances ◽  
2014 ◽  
Vol 4 (94) ◽  
pp. 52241-52244 ◽  
Author(s):  
Laia Josa-Culleré ◽  
Yelena A. Wainman ◽  
Kevin M. Brindle ◽  
Finian J. Leeper
Keyword(s):  
Chemical Reporter ◽  
Strained Alkenes ◽  
Diazo Group

Diazoacetyl groups undergo spontaneous cycloaddition with strained alkenes and alkynes and can be bioorthogonal reporter groups labelling proteins and glycans.

cis-2,3-Di-tert-butylcyclopropanones

1997 ◽  
Vol 75 (7) ◽  
pp. 1030-1040 ◽  
Author(s):  
T.S. Sorensen ◽  
F. Sun
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Carbonyl Group ◽  
Trans Isomer ◽  
Carbonyl Oxygen ◽  
Highly Strained ◽  
Strained Alkenes ◽  
Acyclic Compound

The preparation of the strained cis-2,3-di-tert-butylcyclopropanone 2 from the acyclic compound, α,α′-dibromodineopentyl ketone 1, using a previously reported methodology, is dramatic evidence of both the existence of oxyallyl intermediates in the mechanism of this reaction, and of the integrity with which oxyallyls ring-close to cyclopropanones by a disrotatory route. Because of the bulky cis substituents, cyclopropanone 2 exhibits a number of unusual spectroscopic features (as compared to the trans isomer 5). With the aid of ab initio calculations on 2 and 5, it can be shown that the C2—C3 bond in 2 interacts with the carbonyl π-orbitals, thus causing the carbonyl oxygen to bend 12° out of the plane; this interaction is absent in 5 and the latter has a planar carbonyl group. As with other cyclopropanones, 2 can be photochemically decarbonylated. This process itself appears to be stereospecific even though highly strained alkenes are produced. Cyclopropanone 2 is thermally rearranged to the trans isomer 5 and the kinetics for this are reported; our favoured mechanism involves oxyallyl intermediates. Other reactions of 2 also appear to proceed through these oxyallyl species; for example, alcohols initially add to 2 to give α-alkoxy ends, solutions of 2 enter into very facile diene cycloadditions, and the dimerization of neat 2 also appears to involve these oxyallyl species. Keywords: cyclopropanones, oxyallyl, stereomutation, stereospecific decarbonylation, nonplanar carbonyl.

scholarly journals Mechanism of the Anthracene-Transfer in a Topochemically Controlled Regiospecific Antipodal C60 Difunctionalization

2020 ◽  
Author(s):  
Radu Talmazan ◽  
Klaus R. Liedl ◽  
Bernhard Kräutler ◽  
Maren Podewitz
Keyword(s):  
Noncovalent Interactions ◽  
Interaction Model ◽  
Fullerene Molecule ◽  
Alder Reaction ◽  
Diels Alder ◽  
C60 Fullerene ◽  
Double Decker ◽  
Minimal Distortion ◽  
Unique Reaction ◽  
Anthracene Molecule

Ever since the discovery of fullerenes, their mono- and multi-functionalization by exohedral addition chemistry has been a fundamental topic. A few years ago, a topochemically controlled regiospecific di-functionalization of C60 fullerene by anthracene in the solid state was discovered. In the present work, we analyze the mechanism of this unique reaction, where an anthracene molecule is transferred from one C60 mono-adduct to another one under exclusive formation of equal amounts of C60 and of the difficult to make, highly useful, antipodal C60 bis-adduct. Our herein disclosed dispersion corrected DFT studies show the anthracene transfer to take place in a synchronous retro Diels-Alder/Diels-Alder reaction: an anthracene molecule dissociates only partially from one fullerene when already undergoing bonding interactions with a neighboring fullerene molecule, facilitating the reaction kinetically. Hence, the anthracene transfer occurs via a stabilized intermediate, in which a planar anthracene molecule is sandwiched between two neighboring fullerenes and forms equally strong “double-decker” type π-π stacking interactions with both of these fullerenes. Analysis with the distortion interaction model shows that the anthracene unit of the intermediate is almost planar with minimal distortion. This analysis sheds light on the existence of simultaneous noncovalent interactions engaging both of the two faces of a planar polyunsaturated ring and two convex fullerene surfaces in an unprecedented ‘inverted sandwich’ structure.

scholarly journals Visible-light photoexcitation of pyridine surface complex, leading to selective dehydrogenative cross-coupling with cyclohexane

2018 ◽  
Vol 20 (45) ◽  
pp. 28375-28381 ◽  
Author(s):  
Shimpei Naniwa ◽  
Akanksha Tyagi ◽  
Akira Yamamoto ◽  
Hisao Yoshida
Keyword(s):  
Reaction Mechanism ◽  
Visible Light ◽  
Cross Coupling ◽  
Surface Complex ◽  
Unique Reaction

A pyridine–TiO2 LMCT complex is excited by visible light to achieve selective DCC with cyclohexane via a unique reaction mechanism.

Understanding proton capture and cation-induced dimerization of [Ag29(BDT)12]3−clusters by ion mobility mass spectrometry

2018 ◽  
Vol 20 (11) ◽  
pp. 7593-7603 ◽  
Author(s):  
Papri Chakraborty ◽  
Ananya Baksi ◽  
Sathish Kumar Mudedla ◽  
Abhijit Nag ◽  
Ganesan Paramasivam ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Alkali Metal ◽  
Metal Ions ◽  
Ion Mobility ◽  
Alkali Metal Ions ◽  
Ion Mobility Mass Spectrometry ◽  
Proton Capture ◽  
Unique Reaction

We present a unique reaction of [Ag29(BDT)12]3−cluster with protons and dimerization of the cluster induced by alkali metal ions.

The Zeolite Micropore as a Unique Reaction Field for the Selective Catalytic Reduction of NO by Hydrocarbon

ChemInform ◽  
2003 ◽  
Vol 34 (24) ◽  
Author(s):  
Atsushi Satsuma ◽  
Akira Shichi ◽  
Tadashi Hattori
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Reduction Of No ◽  
Reaction Field ◽  
Unique Reaction
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