Mechanistic Studies on a Cooperative NHC Organocatalysis/Palladium Catalysis System: Uncovering Significant Lessons for Mixed Chiral Pd(NHC)(PR3) Catalyst Design

2017 ◽  
Vol 139 (12) ◽  
pp. 4443-4451 ◽  
Author(s):  
Chang Guo ◽  
Daniel Janssen-Müller ◽  
Mirco Fleige ◽  
Andreas Lerchen ◽  
Constantin G. Daniliuc ◽  
...  
Keyword(s):  
Palladium Catalysis ◽  
Catalyst Design ◽  
Mechanistic Studies

scholarly journals A rational pre-catalyst design for bis-phosphine mono-oxide palladium catalyzed reactions

2017 ◽  
Vol 8 (4) ◽  
pp. 2841-2851 ◽  
Author(s):  
Yining Ji ◽  
Hongming Li ◽  
Alan M. Hyde ◽  
Qinghao Chen ◽  
Kevin M. Belyk ◽  
...  
Keyword(s):  
Rational Design ◽  
Catalyst Design ◽  
Mechanistic Studies ◽  
Catalyst Activation ◽  
Palladium Catalyzed ◽  
Catalyzed Reactions

Detailed mechanistic studies of a Pd-catalyzed asymmetric C–N coupling led to a rational design of a new series of bis-phosphine mono-oxides ligated Pd(ii) pre-catalysts that allow for reliable and complete catalyst activation.

Organocatalyzed coupling of carbon dioxide with epoxides for the synthesis of cyclic carbonates: catalyst design and mechanistic studies

2017 ◽  
Vol 7 (13) ◽  
pp. 2651-2684 ◽  
Author(s):  
M. Alves ◽  
B. Grignard ◽  
R. Mereau ◽  
C. Jerome ◽  
T. Tassaing ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Catalyst Design ◽  
Cyclic Carbonates ◽  
Mechanistic Studies

The coupling of carbon dioxide (CO2) with epoxides with the formation of cyclic carbonates is a highly attractive 100% atom economic reaction. It represents a greener and safer alternative to the conventional synthesis of cyclic carbonates from diols and toxic phosgene.

scholarly journals A case study of proton shuttling in palladium catalysis

2016 ◽  
Vol 7 (3) ◽  
pp. 2179-2187 ◽  
Author(s):  
Julien Monot ◽  
Paul Brunel ◽  
Christos E. Kefalidis ◽  
Noel Ángel Espinosa-Jalapa ◽  
Laurent Maron ◽  
...  
Keyword(s):  
Palladium Catalysis ◽  
Catalytic Performance ◽  
Pincer Complexes ◽  
Mechanistic Studies ◽  
Proton Shuttling

Thanks to mechanistic studies, the catalytic performance of SCS indenediide Pd pincer complexes has been spectacularly enhanced using catechol additives as proton shuttles.

scholarly journals CO2-Mediated Pd-Catalyzed Stereo- and Regioselective Arylation of Free Allylamines

2020 ◽  
Author(s):  
Vinod Landge ◽  
Justin Maxwell ◽  
Pratibha Chand-Thakuri ◽  
Mohit Kapoor ◽  
Evan Diemler ◽  
...  
Keyword(s):  
Catalyst Design ◽  
Powerful Method ◽  
Mechanistic Studies ◽  
Atom Economy ◽  
Biologically Relevant ◽  
Mild Conditions ◽  
Selective Functionalization ◽  
Michael Acceptors ◽  
Key Features ◽  
Terminal Olefins

Mizoroki-Heck couplings are a powerful method for elaborating alkene feedstocks. While selective functionalization of terminal olefins has been achieved by catalyst design, selective functionalization of internal olefins has generally required use of directing groups except in the case of Michael acceptors. Allylamine substrates have typically required protection to be suitable for these reactions, decreasing the step and atom economy of these procedures. Herein we demonstrate that the addition of CO<sub>2</sub> (dry ice) allows for the reproducible stereospecific arylation of both secondary and primary allylamines in the presence of a Pd<sup>II</sup> catalyst. Notably, the product 3,3’-diarylallylamine motif is prevalent in a variety of biologically-relevant structures, and this method represents the most straightforward synthesis of these targets to date. Key features of the method are the ability to access relatively mild conditions that facilitate a broad substrate scope, as well as direct diarylation of terminal allylamine substrates. In addition, several complex and therapeutically-relevant molecules are included to demonstrate the utility of the transformation. Mechanistic studies point to an amine-directed reaction where CO<sub>2</sub> serves to protect the substrate and product from degradation.

Review of Catalyst Design and Mechanistic Studies for the Production of Olefins from Anthropogenic CO2

ACS Catalysis ◽  
2020 ◽  
Vol 10 (23) ◽  
pp. 14258-14282
Author(s):  
Devender Goud ◽  
Rimzhim Gupta ◽  
Raghu Maligal-Ganesh ◽  
Sebastian C. Peter
Keyword(s):  
Catalyst Design ◽  
Mechanistic Studies ◽  
Anthropogenic Co2

scholarly journals Mechanistic investigations of bipyrimidine-promoted palladium-catalyzed allylic acetoxylation of olefins

2009 ◽  
Vol 87 (1) ◽  
pp. 264-271 ◽  
Author(s):  
Bo-Lin Lin ◽  
Jay A Labinger ◽  
John E Bercaw
Keyword(s):  
Acetic Acid ◽  
Key Words ◽  
Palladium Catalysis ◽  
Allylic Oxidation ◽  
Competition Experiment ◽  
Catalyst Precursor ◽  
Mechanistic Studies ◽  
Allyl Acetate ◽  
Palladium Catalyzed ◽  
Terminal Olefins

Several pyridine-like ligands were found to improve Pd(OAc)2-catalyzed allylic oxidation of allylbenzene to cinnamyl acetate by p-benzoquinone in acetic acid. The best ligand examined, bipyrimidine, was used to identify the catalyst precursor for this system, (bipyrimidine)Pd(OAc)2, which was fully characterized. Mechanistic studies suggest the reaction takes place through disproportionation of (bipyrimidine)Pd(OAc)2 to form a bipyrimidine-bridged dimer, which reacts with olefin to form a PdII-olefin adduct, followed by allylic C–H activation to produce (η3-allyl)PdII species. The (η3-allyl)PdII intermediate undergoes a reversible acetate attack to generate a Pd0-(allyl acetate) adduct, which subsequently reacts with p-benzoquinone to release allyl acetate and regenerate (bipyrimidine)Pd(OAc)2. No KIE is observed for the competition experiment between allylbenzene-d0 and allylbenzene-d5 (CD2=CDCD2C6H5), suggesting that allylic C–H activation is not rate-determining. Catalytic allylic acetoxylations of other terminal olefins as well as cyclohexene were also effected by (bipyrimidine)Pd(OAc)2.Key words: olefin, palladium catalysis, allylic C–H oxidation, p-benzoquinone, bipyrimidine.

Mechanistic Studies on Ring-Opening Polymerization of Benzoxazines: A Mechanistically Based Catalyst Design

2011 ◽  
Vol 44 (12) ◽  
pp. 4616-4622 ◽  
Author(s):  
Chao Liu ◽  
Dongmei Shen ◽  
Rosa María Sebastián ◽  
Jordi Marquet ◽  
Rainer Schönfeld
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Catalyst Design ◽  
Mechanistic Studies
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