scholarly journals Recent Progress in N-Heterocyclic Carbene Gold-Catalyzed Reactions of Alkynes Involving Oxidation/Amination/Cycloaddition

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 350 ◽  
Author(s):  
Xiang-Ting Tang ◽  
Fan Yang ◽  
Ting-Ting Zhang ◽  
Yi-Fan Liu ◽  
Si-Yu Liu ◽  
...  
Keyword(s):  
Recent Progress ◽  
Rapid Development ◽  
Gold Catalysis ◽  
Diazo Compounds ◽  
Ancillary Ligands ◽  
Metal Carbenes ◽  
Directing Group ◽  
Catalyzed Reactions ◽  
Exciting Area ◽  
Catalyzed Oxidation

Recent rapid development in homogeneous gold catalysis affords an alternative and particularly thriving strategy for the generation of gold carbenes through gold-catalyzed oxidation/amination/cycloaddition of alkynes, while it avoids the employment of hazardous and potentially explosive diazo compounds as starting materials for carbene generation. In addition to facile and secure operation, gold carbenes generated in this strategy display good chemoselectivity distinct from other metal carbenes produced from the related diazo approach. N-heterocyclic carbene (NHC) gold is a special metal complex that can be used as ancillary ligands, which provides enhanced stability and can also act as an efficient chiral directing group. In this review, we will present an overview of these recent advances in alkyne oxidation/amination/cycloaddition by highlighting their specificity and applicability, aiming to facilitate progress in this very exciting area of research.

Catalytic Deoxygenative Cyclopropanation of 1,2-Dicarbonyl or Monocarbonyl Compounds via Molybdenum Catalysis

Synlett ◽  
2021 ◽  
Author(s):  
Jia-Le Wang ◽  
Chun-Xiang Zhuo
Keyword(s):  
Transition Metal ◽  
Recent Progress ◽  
Diazo Compounds ◽  
Recent Advances ◽  
Metal Carbenes ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

The cyclopropanation of alkenes through the transition-metal-catalyzed decomposition of diazo compounds is a powerful and straightforward strategy to produce cyclopropanes. Nevertheless, the appeal of further application of this strategy is tempered by the potentially explosive nature of the diazo substrates. Therefore, it is highly desirable to develop sustainable and operationally safe surrogates for diazo compounds. In this synpacts article, we discuss recent advances on the cyclopropane syntheses through the catalytic cyclopropanation of alkenes and metal-carbenes generated in-situ from non-diazo precursors, as well as highlight our recent progress on the unprecedented molybdenum-catalyzed deoxygenative cyclopropanation reaction of 1,2-dicarbonyl or monocarbonyl compounds.

Recent progress towards the transition-metal-catalyzed Nazarov cyclization of alkynes via metal carbenes

2021 ◽  
Author(s):  
Wen-Bo Shen ◽  
Guang-Xin Ru ◽  
Ting-Ting Zhang ◽  
Meng Zhang ◽  
Xiao-Lei Jiang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Recent Progress ◽  
Cyclization Reaction ◽  
Diazo Compounds ◽  
Nazarov Cyclization ◽  
Metal Carbenes ◽  
Transition Metal Catalyzed ◽  
Tandem Cyclization ◽  
Metal Catalyzed

In recent years, transition-metal-catalyzed tandem cyclization reaction of alkyne, especially involving metal carbene intermediate, has received worthwhile interest as it bypasses the employment of risky and potentially explosive diazo compounds...

Some results concerning the local analytic branches of an algebraic variety

1953 ◽  
Vol 49 (3) ◽  
pp. 386-396 ◽  
Author(s):  
D. G. Northcott
Keyword(s):  
Algebraic Geometry ◽  
Power Series ◽  
Algebraic Variety ◽  
Recent Progress ◽  
Rapid Development ◽  
Noetherian Rings ◽  
Local Rings ◽  
Power Series Rings ◽  
Analytic Algebra ◽  
Topological Theories

The recent progress of modern algebra in analysing, from the algebraic standpoint, the foundations of algebraic geometry, has been marked by the rapid development of what may be called ‘analytic algebra’. By this we mean the topological theories of Noetherian rings that arise when one uses ideals to define neighbourhoods; this includes, for instance, the theory of power-series rings and of local rings. In the present paper some applications are made of this kind of algebra to some problems connected with the notion of a branch of a variety at a point.

scholarly journals Isomerization of an enzyme-coenzyme complex in yeast alcohol dehydrogenase-catalysed reactions

2003 ◽  
Vol 68 (2) ◽  
pp. 77-84 ◽  
Author(s):  
Vladimir Leskovac ◽  
Svetlana Trivic ◽  
Draginja Pericin
Keyword(s):  
Alcohol Dehydrogenase ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Kinetic Mechanism ◽  
Yeast Alcohol Dehydrogenase ◽  
Catalyzed Reactions ◽  
The Individual ◽  
Individual Rate ◽  
Catalyzed Oxidation

In this work, all the rate constants in the kinetic mechanism of the yeast alcohol dehydrogenase-catalyzed oxidation of ethanol by NAD+, at pH 7.0, 25 ?C, have been estimated. The determination of the individual rate constants was achieved by fitting the reaction progress curves to the experimental data, using the procedures of the FITSIM and KINSIM software package of Carl Frieden. This work is the first report in the literature showing the internal equilibrium constants for the isomerization of the enzyme-NAD+ complex in yeast alcohol dehydrogenase-catalyzed reactions.

Recent Progress of Marine Survey Unmanned Surface Vehicle in China

2019 ◽  
Vol 53 (3) ◽  
pp. 23-29
Author(s):  
Chao Dong ◽  
Xue Li ◽  
Xin-xi Chen ◽  
Jiu-cai Jin ◽  
Cheng-yi Huang
Keyword(s):  
Communication Networks ◽  
Recent Progress ◽  
Rapid Development ◽  
Extreme Environments ◽  
Hydrographic Survey ◽  
Antisubmarine Warfare ◽  
The One ◽  
Mine Countermeasures ◽  
Marine Accidents ◽  
Applied Fields

AbstractBased on the ongoing techniques among control theory, communication networks, and sensor design, unmanned aerial vehicles (UAVs), unmanned undersea vehicles (UUVs) and unmanned surface vehicles (USVs) are experiencing rapid development. Research on these unmanned systems and those intelligent sectors inside has absorbed interests and investments from not only military but also civil organizations. The well-applied fields include surveillance and reconnaissance, surface warfare, antisubmarine warfare, mine countermeasures, oceanic environment monitoring, search and rescue, hydrographic survey, and so on. Comparing with those studies on UAVs and UUVs, the one focusing on USVs was started later and has been developed quickly in the past 20 years. Since 2013, USV has advanced considerably in China, particularly in the marine survey field. Owing to its characteristics of light-weighting, intelligence, and unmanned operations, USV is attractive for shallow water, extreme environments, and marine accidents. This paper comprehensively summarizes the recent progress of the marine survey USV in China. The structure of the paper is divided into three parts. First, we briefly recall the developing history and introduce several excellent USVs of China in recent years. The marine survey USVs invested by the State Oceanic Administration (SOA) are then summarized in the next section, along with the details of hydrographic survey in the South China Sea, Antarctic marine survey, and oil spill emergency response. Finally, the paper points out current deficiencies and future directions of the potential technique.

Rhodium(iii)-catalyzed indole synthesis at room temperature using the transient oxidizing directing group strategy

2019 ◽  
Vol 55 (64) ◽  
pp. 9547-9550 ◽  
Author(s):  
Yaping Shang ◽  
Krishna Jonnada ◽  
Subhash Laxman Yedage ◽  
Hua Tu ◽  
Xiaofeng Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Nitroso Group ◽  
Group Strategy ◽  
Internal Alkynes ◽  
Directing Group ◽  
Catalyzed Reactions ◽  
Indole Synthesis

Rh-Catalyzed reactions of N-alkyl anilines with internal alkynes at room temperature have been developed using an in situ generated N-nitroso group as a transient oxidizing directing group.

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