scholarly journals Regiodivergent Organocatalytic Reactions

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1013
Author(s):  
Mayavan Viji ◽  
Srinu Lanka ◽  
Jaeuk Sim ◽  
Chanhyun Jung ◽  
Heesoon Lee ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Transition Metal ◽  
Cost Effective ◽  
Transition Metal Catalysts ◽  
Cinchona Alkaloids ◽  
Environmentally Benign ◽  
Reaction Pathways ◽  
Reaction Conditions ◽  
Lewis Bases ◽  
Organocatalytic Reactions

Organocatalysts are abundantly used for various transformations, particularly to obtain highly enantio- and diastereomeric pure products by controlling the stereochemistry. These applications of organocatalysts have been the topic of several reviews. Organocatalysts have emerged as one of the very essential areas of research due to their mild reaction conditions, cost-effective nature, non-toxicity, and environmentally benign approach that obviates the need for transition metal catalysts and other toxic reagents. Various types of organocatalysts including amine catalysts, Brønsted acids, and Lewis bases such as N-heterocyclic carbene (NHC) catalysts, cinchona alkaloids, 4-dimethylaminopyridine (DMAP), and hydrogen bond-donating catalysts, have gained renewed interest because of their regioselectivity. In this review, we present recent advances in regiodivergent reactions that are governed by organocatalysts. Additionally, we briefly discuss the reaction pathways of achieving regiodivergent products by changes in conditions such as solvents, additives, or the temperature.

DMSO-Mediated Synthesis of Methylene-Bridged Unsymmetrical Bisamides in the Presence of AcOH

Synthesis ◽  
2019 ◽  
Vol 52 (02) ◽  
pp. 297-303
Author(s):  
Yi Zhang ◽  
Dongheng Zhou ◽  
Yongmin Ma ◽  
Jing Chen
Keyword(s):  
Acetic Acid ◽  
Transition Metal ◽  
Metal Catalysts ◽  
Dual Role ◽  
Transition Metal Catalysts ◽  
Environmentally Benign ◽  
Efficient Procedure ◽  
Effective Synthesis ◽  
New Strategies

A simple and efficient procedure for the synthesis of N-[(methylthio)methyl]benzamides and methylene-bridged unsymmetrical bisamides was achieved mediated by DMSO in the presence of acetic acid. DMSO plays a dual role in the transformation, as not only a solvent, but also an environmentally benign methylene source. The protocol provides new strategies for effective synthesis of unsymmetrical bisamides and avoids the use of transition-metal catalysts.

scholarly journals Straightforward Strategies for the Preparation of NH-Sulfox­imines: A Serendipitous Story

Synlett ◽  
2017 ◽  
Vol 28 (19) ◽  
pp. 2525-2538 ◽  
Author(s):  
James Bull ◽  
Renzo Luisi ◽  
Leonardo Degennaro
Keyword(s):  
Transition Metal ◽  
Physicochemical Properties ◽  
Direct Synthesis ◽  
Transition Metal Catalysts ◽  
Hypervalent Iodine ◽  
Reaction Conditions ◽  
One Pot ◽  
Metal Free ◽  
Recent Developments ◽  
New Procedures

Sulfoximines are emerging as valuable new isosteres for use in medicinal chemistry, with the potential to modulate physicochemical properties. Recent developments in synthetic strategies have made the unprotected ‘free’ NH-sulfoximine group more readily available, facilitating further study. This account reviews approaches to NH-sulfoximines, with a focus on our contribution to the field. Starting from the development of catalytic strategies involving transition metals, more sustainable metal-free processes have been discovered. In particular, the use of hypervalent iodine reagents to mediate NH-transfer to sulfoxides is described, along with an assessment of the substrate scope. Furthermore, a one-pot strategy to convert sulfides directly into NH-sulfoximines is discussed, with N- and O-transfer occurring under the reaction conditions. Mechanistic evidence for the new procedures is included as well as relevant synthetic applications that further exemplify the potential of these approaches.1 Introduction2 Strategies to Form NH-Sulfoximines Involving Transition-Metal Catalysts3 Metal-Free Strategies to Prepare NH-Sulfoximines4 Mechanistic Evidence for the Direct Synthesis of NH-Sulfoximines from Sulfoxides and Sulfides5 Further Applications6 Conclusion

Design of hydroxyapatite-bound transition metal catalysts for environmentally-benign organic syntheses

2004 ◽  
Vol 8 (4) ◽  
pp. 231-239 ◽  
Author(s):  
Kiyotomi Kaneda ◽  
Kohsuke Mori ◽  
Takayoshi Hara ◽  
Tomoo Mizugaki ◽  
Kohki Ebitani
Keyword(s):  
Transition Metal ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Environmentally Benign ◽  
Organic Syntheses

Copper-catalyzed N-(hetero)arylation of amino acids in water

RSC Advances ◽  
2016 ◽  
Vol 6 (99) ◽  
pp. 96762-96767 ◽  
Author(s):  
Krishna K. Sharma ◽  
Meenakshi Mandloi ◽  
Neha Rai ◽  
Rahul Jain
Keyword(s):  
Amino Acids ◽  
Transition Metal ◽  
Cost Effective ◽  
Environmentally Benign ◽  
Cost Effective Method ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

A transition metal-catalyzed, environmentally benign, rapid and cost-effective method for the N-(hetero)arylation of zwitterionic amino acids in water is reported.

Recent Developments in the de Novo Synthesis of Heterocycles by First-Row Transition-Metal-Catalyzed Acceptorless Dehydrogenation

2019 ◽  
Vol 23 (9) ◽  
pp. 1005-1018 ◽  
Author(s):  
V. Arun ◽  
Suman De Sarkar
Keyword(s):  
Transition Metal ◽  
De Novo ◽  
Cost Effective ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
De Novo Synthesis ◽  
Recent Developments ◽  
Key Features ◽  
Imine Compounds ◽  
Metal Catalyzed

Applications of Acceptorless Dehydrogenation (AD) process for the synthesis of important heterocycles are discussed. The key features of AD process are the generation of more reactive carbonyl/imine compounds from alcohols/amines by the release of dihydrogen as a stoichiometric byproduct. In this review, we document recent advances in this field by using first row transition metal catalysts and easily accessible coupling partners, thus offering cost-effective access to different heterocyclic rings.

scholarly journals Electrochemical Umpolung of Bromide: Transition-Metal-Free Bromination of Indole C–H Bond

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 696 ◽  
Author(s):  
Pan Zhang ◽  
Jianbin Chen ◽  
Wei Gao ◽  
Yiting Xiao ◽  
Changwei Liu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electrode Material ◽  
Environmentally Friendly ◽  
Transition Metal Catalysts ◽  
Reaction Conditions ◽  
Metal Free ◽  
Chemical Oxidants ◽  
Bromide Ion ◽  
Environmentally Friendly Approach ◽  
Graphite Rod

A facile and sustainable electrochemical umpolung of bromide ion protocol was developed under mild reaction conditions. Transition metal catalysts and exogenous chemical oxidants were obviated for the bromination of C–H bond. Notably, graphite rod, which is commercially available at supermarkets and is inexpensive, was employed as the electrode material. This operationally easy and environmentally friendly approach accomplished the synthesis of 3-bromoindole in excellent yield and regioselectivity.

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