scholarly journals A New Organocatalytic Desymmetrization Reaction Enables the Enantioselective Total Synthesis of Madangamine E

2021 ◽  
Author(s):  
Shinya Shiomi ◽  
Benjamin D. A. Shennan ◽  
Ken Yamazaki ◽  
Ángel L. Fuentes de Arriba ◽  
Dhananjayan Vasu ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Density Functional ◽  
One Pot ◽  
Functional Theory ◽  
Bond Forming ◽  
Enantioselective Total Synthesis ◽  
Carbon Carbon Bond ◽  
Stereogenic Centers ◽  
Key Steps ◽  
Prochiral Ketone

The enantioselective total synthesis of madangamine E has been completed in 30 steps, enabled by a new catalytic and highly enantioselective desymmetrizing intramolecular Michael addition reaction of a prochiral ketone to a tethered β,β’-disubstituted nitroolefin. This key carbon–carbon bond forming reaction efficiently constructed a chiral bicyclic core in near-perfect enantio- and diastereo-selectivity, concurrently established three stereogenic centers, including a quaternary carbon stereocenter, and proved highly scalable. Furthermore, the pathway and origins of enantioselectivity in this catalytic cyclisation were probed using density functional theory (DFT) calculations, which revealed the crucial substrate/catalyst interactions in the enantio-determining step. Following construction of the bicyclic core, the total synthesis of madangamine E could be completed, with key steps including a mild one-pot oxidation-lactamisation, a two-step Z-selective olefination of a sterically hindered ketone, and ring-closing metatheses to install the two macrocyclic rings.

Microwave-accelerated Carbon-carbon and Carbon-heteroatom Bond Formation via Multi-component Reactions: A Brief Overview

2020 ◽  
Vol 7 (1) ◽  
pp. 23-39 ◽  
Author(s):  
Kantharaju Kamanna ◽  
Santosh Y. Khatavi
Keyword(s):  
Organic Synthesis ◽  
Bond Formation ◽  
Cycloaddition Reaction ◽  
Nanoparticle Synthesis ◽  
Single Step ◽  
Bioactive Molecules ◽  
One Pot ◽  
Bond Forming ◽  
Material Interest ◽  
Carbon Carbon Bond

Multi-Component Reactions (MCRs) have emerged as an excellent tool in organic chemistry for the synthesis of various bioactive molecules. Among these, one-pot MCRs are included, in which organic reactants react with domino in a single-step process. This has become an alternative platform for the organic chemists, because of their simple operation, less purification methods, no side product and faster reaction time. One of the important applications of the MCRs can be drawn in carbon- carbon (C-C) and carbon-heteroatom (C-X; X = N, O, S) bond formation, which is extensively used by the organic chemists to generate bioactive or useful material synthesis. Some of the key carbon- carbon bond forming reactions are Grignard, Wittig, Enolate alkylation, Aldol, Claisen condensation, Michael and more organic reactions. Alternatively, carbon-heteroatoms containing C-N, C-O, and C-S bond are also found more important and present in various heterocyclic compounds, which are of biological, pharmaceutical, and material interest. Thus, there is a clear scope for the discovery and development of cleaner reaction, faster reaction rate, atom economy and efficient one-pot synthesis for sustainable production of diverse and structurally complex organic molecules. Reactions that required hours to run completely in a conventional method can now be carried out within minutes. Thus, the application of microwave (MW) radiation in organic synthesis has become more promising considerable amount in resource-friendly and eco-friendly processes. The technique of microwaveassisted organic synthesis (MAOS) has successfully been employed in various material syntheses, such as transition metal-catalyzed cross-coupling, dipolar cycloaddition reaction, biomolecule synthesis, polymer formation, and the nanoparticle synthesis. The application of the microwave-technique in carbon-carbon and carbon-heteroatom bond formations via MCRs with major reported literature examples are discussed in this review.

Concise Total Synthesis of Curvulone B

Synlett ◽  
2020 ◽  
Author(s):  
Debendra K. Mohapatra ◽  
Shivalal Banoth ◽  
Utkal Mani Choudhury ◽  
Kanakaraju Marumudi ◽  
Ajit C. Kunwar
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Ring System ◽  
Bond Forming ◽  
Cross Metathesis ◽  
Bond Forming Reactions ◽  
Key Steps

AbstractA concise and convergent stereoselective synthesis of curvulone B is described. The synthesis utilized a tandem isomerization followed by C–O and C–C bond-forming reactions following Mukaiyama-type aldol conditions for the construction of the trans-2,6-disubstituted dihydropyran ring system as the key steps. Other important features of this synthesis are a cross-metathesis, epimerization, and Friedel–Crafts acylation.

Synthesis of novel N-functionalized 4-aryl-tetrahydrobiquinoline-2,5-(1H,3H)-diones via one-pot three-component reaction: a joint experimental and computational study

2018 ◽  
Vol 96 (12) ◽  
pp. 1071-1078
Author(s):  
Vahideh Zadsirjan ◽  
Sayyed Jalil Mahdizadeh ◽  
Majid M. Heravi ◽  
Masumeh Heydari
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Computational Study ◽  
Reaction Pathway ◽  
Deep Insight ◽  
One Pot ◽  
Functional Theory ◽  
Three Component Reaction ◽  
High Yields ◽  
Mechanism Of The Reaction

A novel series of N-functionalized 4-aryl-tetrahydrobiquinoline-2,5-(1H,3H)-diones were synthesized in high yields by a one-pot three-component reaction involving 2-chloroquinoline-3-carbaldehydes, Meldrum’s acid, and enaminones (dimedone-based enaminones) in the presence of K2CO3 in CH3CN under reflux condition. To gain a deep insight on the mechanism of the reaction, an extensive series of quantum mechanics calculations in the framework of density functional theory (DFT) were carried out for supporting the suggested reaction pathway.

scholarly journals Enantioselective total synthesis of decytospolide A and decytospolide B using an Achmatowicz reaction

2018 ◽  
Vol 16 (33) ◽  
pp. 5979-5986 ◽  
Author(s):  
Arun K. Ghosh ◽  
Hannah M. Simpson ◽  
Anne M. Veitschegger
Keyword(s):  
Total Synthesis ◽  
Transfer Hydrogenation ◽  
Enantioselective Total Synthesis ◽  
Key Steps ◽  
Enantioselective Syntheses

Enantioselective syntheses of decytospolides are described using an Achmatowicz rearrangement, transfer hydrogenation and Friedel–Crafts acylation as the key steps.

One-Pot Hydroxy Group Activation/Carbon-Carbon Bond Forming Sequence Using a Brønsted Base/Brønsted Acid System

2010 ◽  
Vol 352 (17) ◽  
pp. 2881-2886 ◽  
Author(s):  
Alice Devineau ◽  
Guillaume Pousse ◽  
Catherine Taillier ◽  
Jérôme Blanchet ◽  
Jacques Rouden ◽  
...  
Keyword(s):  
Hydroxy Group ◽  
Bronsted Acid ◽  
Acid System ◽  
Brønsted Acid ◽  
One Pot ◽  
Carbon Bond ◽  
Bond Forming ◽  
Carbon Carbon Bond ◽  
Brönsted Acid ◽  
Brønsted Base

First enantioselective one-pot, three-component imino Reformatsky reaction

2006 ◽  
Vol 78 (2) ◽  
pp. 287-291 ◽  
Author(s):  
Pier Giorgio Cozzi ◽  
Eleonora Rivalta
Keyword(s):  
Simple Procedure ◽  
Enantiomeric Excess ◽  
Multiple Roles ◽  
Reformatsky Reaction ◽  
One Pot ◽  
Bond Forming ◽  
Carbon Carbon Bond ◽  
Three Component Reaction ◽  
Hydroxy Esters ◽  
The Reformatsky Reaction

The Reformatsky reaction is the well-recognized carbon-carbon bond-forming reaction of α-halo esters with aldehydes or ketones in the presence of Zn metal to give β-hydroxy esters. Recently, it has been reported that Rh- and Ni-catalyzed Reformatsky reaction, in which R2Zn (R = Me, Et) acts as the Zn source, reacted smoothly with carbonyl compounds and imines. Taking advantage of N-methylephedrine as a cheap and recoverable chiral ligand, we have discovered the first homogeneous enantioselective Ni-catalyzed imino Reformatsky reaction. The process is a one-pot, three-component reaction, in which Me2Zn plays multiple roles as dehydrating agent, reductant, and coordinating metal. Broad scope, high enantiomeric excess, and a simple procedure are adding value to our findings.

scholarly journals Ultrabright bimetallic AuAg complex: From luminescence mechanism to biological application

2020 ◽  
Vol 13 (05) ◽  
pp. 2041001 ◽  
Author(s):  
Junchi Chen ◽  
Lingfang Liu ◽  
Haile Liu ◽  
Yonghui Li ◽  
Junying Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Biomedical Applications ◽  
Density Functional ◽  
Metal Clusters ◽  
One Pot ◽  
Functional Theory ◽  
Two Photon ◽  
Photon Excitation ◽  
Lowest Unoccupied Molecular Orbital ◽  
Good Biocompatibility

Metal clusters have attracted wide interests due to their unique electronic and optical properties, but the low luminescence quantum yield (QY) prevents them from potential biomedical applications. In this work, silver-doped Au nanoclusters (NCs) are shown to be able to improve the QY of metal clusters. We succeeded in synthesizing ultrabright glutathione (GSH) protected AuAg clusters with 10.8% QY by a one-pot route. Their florescence is about 7.5 times brighter than pure Au NCs, with super photostability and good biocompatibility in physiological environment. Based on density functional theory (DFT) calculations, we investigated the electronic structures and optical properties of the AuAg NCs. The results show that the increase of the density of states of the lowest unoccupied molecular orbital (LUMO) leads to the fluorescence enhancement. In addition, two-photon excitation fluorescence imaging has been performed to show their great potential for biomedicine.

scholarly journals Polar molecules catalyze CO insertion into metal-alkyl bonds through the displacement of an agostic C-H bond

2019 ◽  
Vol 116 (9) ◽  
pp. 3419-3424
Author(s):  
Tian Zhou ◽  
Santanu Malakar ◽  
Steven L. Webb ◽  
Karsten Krogh-Jespersen ◽  
Alan S. Goldman
Keyword(s):  
Transition Metal Complexes ◽  
Density Functional ◽  
Organic Molecules ◽  
Polar Molecules ◽  
Functional Theory ◽  
Bond Forming ◽  
Co Insertion ◽  
The Subject ◽  
Kinetics Of

The insertion of CO into metal-alkyl bonds is the key C-C bond-forming step in many of the most important organic reactions catalyzed by transition metal complexes. Polar organic molecules (e.g., tetrahydrofuran) have long been known to promote CO insertion reactions, but the mechanism of their action has been the subject of unresolved speculation for over five decades. Comprehensive computational studies [density functional theory (DFT)] on the prototypical system Mn(CO)5(arylmethyl) reveal that the polar molecules do not promote the actual alkyl migration step. Instead, CO insertion (i.e. alkyl migration) occurs rapidly and reversibly to give an acyl complex with a sigma-bound (agostic) C-H bond that is not easily displaced by typical ligands (e.g. phosphines or CO). The agostic C-H bond is displaced much more readily, however, by the polar promoter molecules, even though such species bind only weakly to the metal center and are themselves then easily displaced; the facile kinetics of this process are attributable to a hydrogen bonding-like interaction between the agostic C-H bond and the polar promoter. The role of the promoter is to thereby catalyze isomerization of the agostic product of CO insertion to give an η2-C,O-bound acyl product that is more easily trapped than the agostic species. This ability of such promoters to displace a strongly sigma-bound C-H bond and to subsequently undergo facile displacement themselves is without reported precedent, and could have implications for catalytic reactions beyond carbonylation.

Using a traceless directing group for the silver-mediated synthesis of 3-trifluoromethylpyrazoles: a computational study on the mechanism and origins of regioselectivity

2018 ◽  
Vol 5 (23) ◽  
pp. 3374-3381 ◽  
Author(s):  
Feiyun Jia ◽  
Jiewei Luo ◽  
Bo Zhang
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Computational Study ◽  
One Pot ◽  
Functional Theory ◽  
One Pot Synthesis ◽  
Directing Group

The silver-mediated one-pot synthesis of 3-trifluoromethylpyrazoles using a traceless directing group was investigated by density functional theory (DFT) calculations.

Sign in / Sign up

Export Citation Format

Share Document