scholarly journals Ring-opening carbonyl–olefin metathesis of norbornenes

2020 ◽  
Vol 11 (30) ◽  
pp. 7884-7895
Author(s):  
Janis Jermaks ◽  
Phong K. Quach ◽  
Zara M. Seibel ◽  
Julien Pomarole ◽  
Tristan H. Lambert
Keyword(s):  
Experimental Study ◽  
Olefin Metathesis ◽  
Ring Opening ◽  
Second Generation

A computational and experimental study has uncovered a second generation hydrazine that enables the catalytic ring-opening carbonyl–olefin metathesis of norbornenes.

scholarly journals Ring-Opening Carbonyl-Olefin Metathesis of Norbornenes

2019 ◽  
Author(s):  
Janis Jermaks ◽  
Phong K. Quach ◽  
Zara M. Seibel ◽  
Julien Pomarole ◽  
Tristan Lambert
Keyword(s):  
Experimental Study ◽  
Theoretical Investigation ◽  
Olefin Metathesis ◽  
Ring Opening ◽  
Activation Barrier ◽  
Reaction Pathway ◽  
Next Generation ◽  
Methyl Group ◽  
Optimized Conditions ◽  
Hydrolysis Of

<div> <p>A computational and experimental study of the hydrazine-catalyzed ring-opening carbonyl-olefin metathesis of norbornenes is described. Detailed theoretical investigation of the energetic landscape for the full reaction pathway with six different hydrazines revealed several crucial aspects for the design of next-generation hydrazine catalysts. This study indicated that a [2.2.2]-bicyclic hydrazine should offer substantially increased reactivity versus the previously reported [2.2.1]-hydrazine due to a lowered activation barrier for the rate-determining cycloreversion step, a prediction which was verified experimentally. Optimized conditions for both cycloaddition and cycloreversion steps were identified, and a brief substrate scope study for each was conducted. A complication for catalysis was found to be the slow hydrolysis of the ring-opened hydrazonium intermediates, which were shown to suffer from a competitive and irreversible cycloaddition with a second equivalent of norbornene. This problem was overcome by the strategic incorporation of a bridgehead methyl group on the norbornene ring, leading to the first demonstrated catalytic carbonyl-olefin metathesis of norbornene rings.</p> </div>

scholarly journals Ring-Opening Carbonyl-Olefin Metathesis of Norbornenes

2019 ◽  
Author(s):  
Janis Jermaks ◽  
Phong K. Quach ◽  
Zara M. Seibel ◽  
Julien Pomarole ◽  
Tristan Lambert
Keyword(s):  
Experimental Study ◽  
Theoretical Investigation ◽  
Olefin Metathesis ◽  
Ring Opening ◽  
Activation Barrier ◽  
Reaction Pathway ◽  
Next Generation ◽  
Methyl Group ◽  
Optimized Conditions ◽  
Hydrolysis Of

<div> <p>A computational and experimental study of the hydrazine-catalyzed ring-opening carbonyl-olefin metathesis of norbornenes is described. Detailed theoretical investigation of the energetic landscape for the full reaction pathway with six different hydrazines revealed several crucial aspects for the design of next-generation hydrazine catalysts. This study indicated that a [2.2.2]-bicyclic hydrazine should offer substantially increased reactivity versus the previously reported [2.2.1]-hydrazine due to a lowered activation barrier for the rate-determining cycloreversion step, a prediction which was verified experimentally. Optimized conditions for both cycloaddition and cycloreversion steps were identified, and a brief substrate scope study for each was conducted. A complication for catalysis was found to be the slow hydrolysis of the ring-opened hydrazonium intermediates, which were shown to suffer from a competitive and irreversible cycloaddition with a second equivalent of norbornene. This problem was overcome by the strategic incorporation of a bridgehead methyl group on the norbornene ring, leading to the first demonstrated catalytic carbonyl-olefin metathesis of norbornene rings.</p> </div>

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

End Capping Ring-Opening Olefin Metathesis Polymerization Polymers with Vinyl Lactones

2008 ◽  
Vol 130 (33) ◽  
pp. 11040-11048 ◽  
Author(s):  
Stefan Hilf ◽  
Robert H. Grubbs ◽  
Andreas F. M. Kilbinger
Keyword(s):  
Olefin Metathesis ◽  
Ring Opening ◽  
Metathesis Polymerization ◽  
End Capping

Experimental Study of the Stereomutation of 1,1-Difluoro-2-ethyl-3-methylcyclopropane Confirms the Predicted Preference for Disrotatory Ring Opening and Closure

1998 ◽  
Vol 120 (24) ◽  
pp. 6187-6188 ◽  
Author(s):  
Feng Tian ◽  
Scott B. Lewis ◽  
Michael D. Bartberger ◽  
William R. Dolbier ◽  
Weston Thatcher Borden
Keyword(s):  
Experimental Study ◽  
Ring Opening

Operation of the Boomerang Mechanism in Olefin Metathesis Reactions Promoted by the Second-Generation Hoveyda Catalyst

ACS Catalysis ◽  
2014 ◽  
Vol 4 (7) ◽  
pp. 2387-2394 ◽  
Author(s):  
Jennifer M. Bates ◽  
Justin A. M. Lummiss ◽  
Gwendolyn A. Bailey ◽  
Deryn E. Fogg
Keyword(s):  
Olefin Metathesis ◽  
Second Generation ◽  
Metathesis Reactions

Regioselectivity of Stoichiometric Metathesis of Vinylsilanes with Second-Generation Grubbs Catalyst: A Combined DFT and Experimental Study

2016 ◽  
Vol 35 (5) ◽  
pp. 621-628 ◽  
Author(s):  
Paweł Śliwa ◽  
Kamil Kurleto ◽  
Jarosław Handzlik ◽  
Szymon Rogalski ◽  
Patrycja Żak ◽  
...  
Keyword(s):  
Experimental Study ◽  
Second Generation ◽  
Grubbs Catalyst
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