Self-Aggregation Tendency of All Species Involved in the Catalytic Cycle of Bifunctional Transfer Hydrogenation

2009 ◽  
Vol 28 (4) ◽  
pp. 960-967 ◽  
Author(s):  
Gianluca Ciancaleoni ◽  
Cristiano Zuccaccia ◽  
Daniele Zuccaccia ◽  
Eric Clot ◽  
Alceo Macchioni
Keyword(s):  
Catalytic Cycle ◽  
Transfer Hydrogenation ◽  
Aggregation Tendency ◽  
Self Aggregation

Self-Aggregation Tendency of Zirconocenium Ion Pairs Which Model Polymer-Chain-Carrying Species in Aromatic and Aliphatic Solvents with Low Polarity

2008 ◽  
Vol 14 (22) ◽  
pp. 6589-6592 ◽  
Author(s):  
Luca Rocchigiani ◽  
Cristiano Zuccaccia ◽  
Daniele Zuccaccia ◽  
Alceo Macchioni
Keyword(s):  
Polymer Chain ◽  
Ion Pairs ◽  
Aggregation Tendency ◽  
Self Aggregation

scholarly journals Nickel-catalyzed intermolecular oxidative Heck arylation driven by transfer hydrogenation

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Honggui Lv ◽  
Huiying Kang ◽  
Biying Zhou ◽  
Xiaosong Xue ◽  
Keary M. Engle ◽  
...  
Keyword(s):  
Nickel Catalyst ◽  
Heck Reaction ◽  
Boronic Acids ◽  
Phosphine Ligand ◽  
Catalytic Cycle ◽  
Transfer Hydrogenation ◽  
Heck Coupling ◽  
Coordination Environment ◽  
Heck Arylation ◽  
Directing Group

Abstract The conventional oxidative Heck reaction between aryl boronic acids and alkenes typically involved the PdII/Pd0/PdII catalytic cycle incorporating an external oxidant and often suffered C=C bond isomerization for internal alkyl-substituted alkenes via chain-walking. Herein, we demonstrate that the regioselectivity (γ-selectivity vs. δ-selectivity) and pathway selectivity (hydroarylation vs. oxidative Heck coupling) of a directed Ni-catalyzed alkene arylation can be controlled by judicious tuning of the coordination environment around the nickel catalyst via optimization of an appropriate phosphine ligand and directing group. In this way, the Ni(0)-catalyzed oxidative Heck arylation that relies on transfer hydrogenation of an acceptor olefin is developed with excellent E/Z selectivity and regioselectivity. Mechanistic investigations suggest that the addition of the acceptor is crucial for lowering the energy for carbometalation and for enabling catalytic turnover.

Synthesis, Characterization, Interionic Structure, and Self-Aggregation Tendency of Zirconaaziridinium Salts Bearing Long Alkyl Chains

2011 ◽  
Vol 30 (1) ◽  
pp. 100-114 ◽  
Author(s):  
Luca Rocchigiani ◽  
Gianfranco Bellachioma ◽  
Gianluca Ciancaleoni ◽  
Alceo Macchioni ◽  
Daniele Zuccaccia ◽  
...  
Keyword(s):  
Alkyl Chains ◽  
Aggregation Tendency ◽  
Self Aggregation

Boron-Catalyzed Hydrogenative Reduction of Substituted Quinolines to Tetrahydroquinolines with Hydrosilanes

Synlett ◽  
2017 ◽  
Vol 28 (18) ◽  
pp. 2396-2400 ◽  
Author(s):  
Sehoon Park ◽  
Sukbok Chang ◽  
Narasimhulu Gandhamsetty
Keyword(s):  
Initial Step ◽  
Reducing Agents ◽  
Catalytic Cycle ◽  
Transfer Hydrogenation ◽  
Mechanistic Studies ◽  
Metal Free ◽  
Substituted Quinolines ◽  
Optimized Conditions ◽  
Hydroxy Groups

A metal-free procedure for the hydrogenative reduction of substituted N-heteroaromatics has been developed by using hydrosilanes as reducing agents. The optimized conditions were successfully applied to the reactions of quinolines, quinoxalines, and quinoline N-oxides. They were also effective for the reduction of quinolines bearing amino or hydroxy groups, where H2 was evolved through dehydrogenative silylation of the amine or hydroxy moieties. Preliminary mechanistic studies revealed that the initial step in the catalytic cycle involves 1,4-addition of the hydrosilane to the quinoline to give a 1,4-dihydroquinoline; this is followed by (transfer) hydrogenation to deliver the tetrahydroquinoline as the final product.

PGSE NMR Studies on DAB-Organo-Rhodium Dendrimers:  Evaluation of the Molecular Size, Self-Aggregation Tendency, and Surface Metal Density

2006 ◽  
Vol 25 (9) ◽  
pp. 2201-2208 ◽  
Author(s):  
Daniele Zuccaccia ◽  
Luigi Busetto ◽  
M. Cristina Cassani ◽  
Alceo Macchioni ◽  
Rita Mazzoni
Keyword(s):  
Molecular Size ◽  
Nmr Studies ◽  
Surface Metal ◽  
Pgse Nmr ◽  
Aggregation Tendency ◽  
Self Aggregation

The Structure and Rearrangements of a Complete Polyketide Synthase Module During its Catalytic Cycle

Planta Medica ◽  
2013 ◽  
Vol 79 (10) ◽  
Author(s):  
DH Sherman ◽  
G Skiniotis ◽  
JL Smith ◽  
K Håkansson ◽  
S Dutta ◽  
...  
Keyword(s):  
Polyketide Synthase ◽  
Catalytic Cycle

Self-Aggregation of Synthetic Protobacteriochlorophyll-d Derivatives

2004 ◽  
Author(s):  
Hitoshi Tamiaki ◽  
Hiroyuki Kitamoto ◽  
Takuya Watanabe ◽  
Reiko Shibata
Keyword(s):  
Self Aggregation

Catalytic, Enantioselective Syn-Diamination of Alkenes

2019 ◽  
Author(s):  
Zhonglin Tao ◽  
Brad Gilbert ◽  
Scott Denmark
Keyword(s):  
General Solution ◽  
Organic Synthesis ◽  
Medicinal Chemistry ◽  
Catalytic Cycle ◽  
Bifunctional Nucleophile

The enantioselective, vicinal diamination of alkenes represents one of the stereocontrolled additions that remains an outstanding challenge in organic synthesis. A general solution to this problem would enable the efficient and selective preparation of widely useful, enantioenriched diamines for applications in medicinal chemistry and catalysis. In this Article we describe the first enantioselective, <i>syn-</i>diamination of simple alkenes mediated by a chiral, enantioenriched organoselenium catalyst together with a <i>N,N’-</i>bistosyl urea as the bifunctional nucleophile and <i>N-</i>fluorocollidinium tetrafluoroborate as the stoichiometric oxidant. Diaryl, aryl-alkyl, and alkyl-alkyl olefins bearing a variety of substituents are all diaminated in consistently high enantioselectivities selectivities but variable yields. The reaction likely proceeds through a Se(II)/Se(IV) redox catalytic cycle reminiscent of the <i>syn-</i>dichlorination reported previously. Furthermore, the <i>syn</i>-stereospecificity of the transformation shows promise for highly enantioselective diaminations of alkenes with no strong steric or electronic bias.

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