scholarly journals Rhodium(III)-Catalyzed [4+2] Annulation via C-H Activation: Synthesis of Multi-Substituted Naphthalenone Sulfoxonium Ylides

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1884 ◽  
Author(s):  
Xiaohan Song ◽  
Xu Han ◽  
Rui Zhang ◽  
Hong Liu ◽  
Jiang Wang
Keyword(s):  
Reaction Mechanism ◽  
Reaction Conditions ◽  
Practical Utility ◽  
Neutral Reaction ◽  
New Type ◽  
Substrate Tolerance

A convenient Rh(III)-catalyzed C-H activation and cascade [4+2] annulation for the synthesis of naphthalenone sulfoxonium ylides has been developed. This method features perfect regioselectivity, mild and redox-neutral reaction conditions, and broad substrate tolerance with good to excellent yields. Preliminary mechanistic experiments were conducted and a plausible reaction mechanism was proposed. The new type naphthalenone sulfoxonium ylides could be further transformed into multi-substituted naphthols, which demonstrates the practical utility of this methodology.

scholarly journals Ring-Opening Copolymerization of Cyclohexene Oxide and Cyclic Anhydrides Catalyzed by Bimetallic Scorpionate Zinc Catalysts

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1651
Author(s):  
Felipe de la Cruz-Martínez ◽  
Marc Martínez de Sarasa Buchaca ◽  
Almudena del Campo-Balguerías ◽  
Juan Fernández-Baeza ◽  
Luis F. Sánchez-Barba ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Mechanism ◽  
Catalytic System ◽  
Phthalic Anhydride ◽  
Ring Opening ◽  
High Selectivity ◽  
Zinc Complexes ◽  
Cyclohexene Oxide ◽  
Reaction Conditions ◽  
Cyclic Anhydrides

The catalytic activity and high selectivity reported by bimetallic heteroscorpionate acetate zinc complexes in ring-opening copolymerization (ROCOP) reactions involving CO2 as substrate encouraged us to expand their use as catalysts for ROCOP of cyclohexene oxide (CHO) and cyclic anhydrides. Among the catalysts tested for the ROCOP of CHO and phthalic anhydride at different reaction conditions, the most active catalytic system was the combination of complex 3 with bis(triphenylphosphine)iminium as cocatalyst in toluene at 80 °C. Once the optimal catalytic system was determined, the scope in terms of other cyclic anhydrides was broadened. The catalytic system was capable of copolymerizing selectively and efficiently CHO with phthalic, maleic, succinic and naphthalic anhydrides to afford the corresponding polyester materials. The polyesters obtained were characterized by spectroscopic, spectrometric, and calorimetric techniques. Finally, the reaction mechanism of the catalytic system was proposed based on stoichiometric reactions.

Local structural changes in polyamorphous (Ni,Fe)Ox electrocatalysts suggest a dual-site oxygen evolution reaction mechanism

2021 ◽  
Author(s):  
Martin Schon ◽  
Oliver Calderon ◽  
Nick Randell ◽  
Santiago Jimenez Villegas ◽  
Katelynn M. Daly ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Structural Changes ◽  
Mixed Metal Oxides ◽  
Reaction Conditions ◽  
Nickel Iron ◽  
Alkaline Reaction ◽  
Dual Site ◽  
Economical Alternative

Amorphous nickel-iron mixed metal oxides have been shown to be extremely efficient oxygen evolution reaction (OER) electrocatalysts with good stability in alkaline reaction conditions. Thus, they offer an economical alternative...

A New Simple Procedure for the Synthesis of Heptamethyl Cyclohepta-1,3,5-triene-1,2,3,4,5,6,7-heptacarboxylate

Synlett ◽  
2018 ◽  
Vol 29 (09) ◽  
pp. 1157-1160 ◽  
Author(s):  
Alexander Belyy ◽  
Dmitry Platonov ◽  
Rinat Salikov ◽  
Anastasiya Levina ◽  
Yury Tomilov
Keyword(s):  
Reaction Mechanism ◽  
Nmr Spectroscopy ◽  
Simple Procedure ◽  
Reaction Conditions

A new and simple procedure for the synthesis of heptamethyl cyclohepta-1,3,5-triene-1,2,3,4,5,6,7-heptacarboxylate in a 51% yield is presented. An optimization of the reaction conditions was performed, and a convenient protocol for the isolation of the reaction product was developed. The structure of the key electrophilic intermediate was determined by means of NMR spectroscopy, and a plausible reaction mechanism is proposed.

scholarly journals Enzyme catalysis as a chain reaction

1991 ◽  
Vol 279 (3) ◽  
pp. 855-861 ◽  
Author(s):  
S E Szedlacsek ◽  
R G Duggleby ◽  
M O Vlad
Keyword(s):  
Reaction Mechanism ◽  
Kinetic Mechanism ◽  
Point Of View ◽  
Simple Type ◽  
Chain Reaction ◽  
Proposed Model ◽  
New Type ◽  
A Chain ◽  
Theoretical Considerations ◽  
Classical Mechanism

A new type of enzyme kinetic mechanism is suggested by which catalysis may be viewed as a chain reaction. A simple type of one-substrate/one-product reaction mechanism has been analysed from this point of view, and the kinetics, in both the transient and the steady-state phases, has been reconsidered. This analysis, as well as literature data and theoretical considerations, shows that the proposed model is a generalization of the classical ones. As a consequence of the suggested mechanism, the expressions, and in some cases even the significance of classical constants (Km and Vmax.), are altered. Moreover, this mechanism suggests that, between two successive enzyme-binding steps, more than one catalytic act could be accomplished. The reaction catalysed by alcohol dehydrogenase was analysed, and it was shown that this chain-reaction mechanism has a real contribution to the catalytic process, which could become exclusive under particular conditions. Similarly, the mechanism of glycogen phosphorylase is considered, and two partly modified versions of the classical mechanism are proposed. They account for both the existing experimental facts and suggest the possibility of chain-reaction pathways for any polymerase.

Synthesis of Yuehchukene Analogues, Murrapanine and Normurrapanine Utylizing Thermal Reaction of b-(1-Hydroxybutenyl)indoles under Neutral Reaction Conditions

Heterocycles ◽  
1996 ◽  
Vol 43 (8) ◽  
pp. 1751 ◽  
Author(s):  
Jyh-Horng Sheu ◽  
Yua-Kuang Chen ◽  
Huey-Fen Chung ◽  
Ping-Jyun Sung ◽  
Song-Fong Lin
Keyword(s):  
Thermal Reaction ◽  
Reaction Conditions ◽  
Neutral Reaction
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