Mechanistic Investigations into the Behavior of a Labeled Zirconocene Polymerization Catalyst

2012 ◽  
Vol 31 (5) ◽  
pp. 2097-2107 ◽  
Author(s):  
Beth M. Moscato ◽  
Bolin Zhu ◽  
Clark R. Landis
Keyword(s):  
Polymerization Catalyst ◽  
Mechanistic Investigations

Three-Component [1+1+1] Cyclopropanation with Ruthenium(II)

2018 ◽  
Author(s):  
Tanner C. Jankins ◽  
Robert R. Fayzullin ◽  
Eugene Khaskin
Keyword(s):  
Quaternary Carbon ◽  
Poor Control ◽  
One Step ◽  
Synthetic Routes ◽  
Mechanistic Investigations ◽  
Chiral Centers ◽  
Metal Catalyzed ◽  
The Right ◽  
Substituted Cyclopropanes

We report a one-step, Ru(II)-catalyzed cyclopropanation reaction that is conceptually different from the previously reported protocols that include Corey-Chaykovsky, Simmons-Smith, and metal catalyzed carbene attack on olefins. Under the current protocol, various alcohols are transformed into sulfone substituted cyclopropanes with excellent isolated yields and diastereoselectivities. This new reaction forms highly congested cyclopropane products with three new C–C bonds, three or two new chiral centers and one new quaternary carbon center. 22 examples of isolated substrates are given. Previously reported synthetic routes for similar substrates are all multi-step, linear routes that proceed with overall low yields and poor control of stereochemistry. Experimental mechanistic investigations suggest initial metal-catalyzed dehydrogenation of the alcohol substrate and catalyst independent stepwise attack of two equivalents of sulfone on the aldehyde under basic conditions. While the Ru(II) is only responsible for the initial dehydrogenation step, the rate of aldehyde formation is crucial to maintaining the right balance of intermediates needed to afford the cyclopropane product.

Visible Light-Induced Sulfonylation/Arylation of Styrenes in a Double Radical Three-Component Photoredox Reaction

2019 ◽  
Author(s):  
Benjamin Lipp ◽  
Lisa Marie Kammer ◽  
Murat Kucukdisli ◽  
Adriana Luque ◽  
Jonas Kühlborn ◽  
...  
Keyword(s):  
Visible Light ◽  
Radical Formation ◽  
Three Component Reaction ◽  
Broad Variety ◽  
Styrene Derivatives ◽  
Mechanistic Investigations

Simultaneous sulfonylation/arylation of styrene derivatives is achieved in a photoredox-catalyzed three-component reaction using visible light. A broad variety of difunctionalized products is accessible in mostly excellent yields and high diastereoselectivity. The developed reaction is scalable and suitable for the modification of styrene-functionalized biomolecules. Mechanistic investigations suggest the transformation to be operating through a designed sequence of radical formation and radical combination.<br>

Scope and Mechanistic Investigations of Pd-Catalyzed Coupling/Cyclization and Cycloisomerization of Allenyl Malonates

ACS Catalysis ◽  
2021 ◽  
pp. 9485-9494
Author(s):  
Logan E. Vine ◽  
Ryan D. Reeves ◽  
Eleanor M. Landwehr ◽  
Israel Fernández ◽  
Jennifer M. Schomaker
Keyword(s):  
Mechanistic Investigations

scholarly journals Recent Advances in bis-Chalcone-Based Photoinitiators of Polymerization: From Mechanistic Investigations to Applications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3192
Author(s):  
Nicolas Giacoletto ◽  
Frédéric Dumur
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Cationic Polymerization ◽  
Free Radical Polymerization ◽  
Research Field ◽  
4D Printing ◽  
Unique Structure ◽  
The Past ◽  
Mechanistic Investigations ◽  
Active Research

Over the past several decades, photopolymerization has become an active research field, and the ongoing efforts to develop new photoinitiating systems are supported by the different applications in which this polymerization technique is involved—including dentistry, 3D and 4D printing, adhesives, and laser writing. In the search for new structures, bis-chalcones that combine two chalcones’ moieties within a unique structure were determined as being promising photosensitizers to initiate both the free-radical polymerization of acrylates and the cationic polymerization of epoxides. In this review, an overview of the different bis-chalcones reported to date is provided. Parallel to the mechanistic investigations aiming at elucidating the polymerization mechanisms, bis-chalcones-based photoinitiating systems were used for different applications, which are detailed in this review.

scholarly journals Mechanistic Investigations into the Catalytic Levulinic Acid Hydrogenation, Insight in H/D Exchange Pathways, and a Synthetic Route to d8-γ-Valerolactone

ACS Catalysis ◽  
2021 ◽  
pp. 10467-10477
Author(s):  
Qingqing Yuan ◽  
Henk H. van de Bovenkamp ◽  
Zhenlei Zhang ◽  
Anna S. Piskun ◽  
Selim Sami ◽  
...  
Keyword(s):  
Levulinic Acid ◽  
Synthetic Route ◽  
Mechanistic Investigations
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