From Propargylic Fluorinations to [1,3]-Rearrangements: Anion and Ligand Effects in Cu-Acetylide Chemistry

Synlett ◽  
2018 ◽  
Vol 29 (13) ◽  
pp. 1675-1682 ◽  
Author(s):  
Christopher Cordier ◽  
Li-Jie Cheng ◽  
Alexander Brown
Keyword(s):  
Reactive Intermediates ◽  
Copper Catalysis ◽  
Mechanistic Studies ◽  
Ligand Effects ◽  
The Past ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Nucleophilic Fluorination

Metal-catalyzed reactions of propargylic substrates have been widely studied. Of this reaction class, Cu-catalyzed methods have received much attention within the past decade, with Cu-allenylidenes being proposed as key reactive intermediates. This Synpacts article will outline our development of a nucleophilic fluorination protocol of propargylic electrophiles using copper catalysis. Following an analysis of the importance of anion and ligand effects, this study led us to the unexpected discovery of a formal [1,3]-rearrangement of O-propargylic alkoxypyridine derivatives that was later rendered enantioselective. By contrast to Cu-allenylidene proposals, our mechanistic findings have identified alternatives involving bimetallic intermediates.1 Introduction2 Propargylic Fluorination3 Anion Effects4 Propargylic Rearrangements5 Mechanistic Studies6 Conclusions

Alkylation Reactions with Alkylsulfonium Salts

Synthesis ◽  
2021 ◽  
Author(s):  
Ze-Yu Tian ◽  
Yu Ma ◽  
Cheng-Pan Zhang
Keyword(s):  
Organic Molecules ◽  
High Efficiency ◽  
Building Blocks ◽  
Organometallic Reagents ◽  
The Past ◽  
Wide Range ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Alkylation Reactions

Application of alkylsulfonium salts as alkyl transfer reagents in organic synthesis has reemerged over the past years. Numerous heteroatom- and carbon-centered nucleophiles, alkenes, arenes, alkynes, organometallic reagents, and others were readily alkylated by alkylsulfonium salts under mild conditions. The reactions feature convenience, high efficiency, readily accessible and structurally diversified alkylation reagents, good functional group tolerance, and a wide range of substrate types, allowing for facile synthesis of various useful organic molecules from the commercially available building blocks. This review summarizes the alkylation reactions using either isolated or in situ formed alkylsulfonium salts via nucleophilic substitution, transition-metal-catalyzed reactions, and photoredox processes.

Recent Advances in Denitrogenative Reactions of Pyridotriazoles

Synthesis ◽  
2020 ◽  
Vol 52 (23) ◽  
pp. 3564-3576 ◽  
Author(s):  
Ilya P. Filippov ◽  
Gleb D. Titov ◽  
Nikolai V. Rostovskii
Keyword(s):  
Lewis Acids ◽  
Heterocyclic Compounds ◽  
Short Review ◽  
Diazo Compounds ◽  
Metal Compounds ◽  
The Past ◽  
Recent Advances ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Chain Isomerization

AbstractDiazo compounds display versatile reactivity and therefore are widely used in organic synthesis. Diazo compounds bearing a 2-pyridyl or a related azine moiety on the diazo carbon exist in the form of fused 1,2,3-triazoles. In this short review, we summarize the recent advances in denitrogenative reactions of [1,2,3]triazolo[1,5-a]pyridines (‘pyridotriazoles’) and related fused 1,2,3-triazoles. Over the past decade, there has been a surge of activity in this field, with novel denitrogenative reactions of pyridotriazoles induced by metal compounds, light, and Brønsted and Lewis acids having been devised. As a result, heterocyclic compounds and functionalized α-picolines as well as bio­active molecules have been synthesized. In the review, emphasis is also placed on the mechanisms of the new reactions.1 Introduction2 Ring-Chain Isomerization of Pyridotriazoles3 Metal-Catalyzed Reactions3.1 Rh(II) Catalysis3.2 Rh(III) Catalysis3.3 Cu Catalysis3.4 Pd Catalysis3.5 Catalysis by Other Metals4 Metal-Free Reactions5 Conclusion

ChemInform Abstract: Ligand Effects in the Metal-Catalyzed Reactions of N-Aryldiazoamides: Ylide Formation vs. Insertion Reactions.

ChemInform ◽  
2010 ◽  
Vol 29 (46) ◽  
pp. no-no
Author(s):  
C. J. MOODY ◽  
S. MIAH ◽  
A. M. Z. SLAWIN ◽  
D. J. MANSFIELD ◽  
I. C. RICHARDS
Keyword(s):  
Insertion Reactions ◽  
Ligand Effects ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Transition Metal Catalyzed C-H bond Activation/Functionalization and Annulation of Phthalazinones

2021 ◽  
Author(s):  
Chandrasekaran Sivaraj ◽  
Alagumalai Ramkumar ◽  
Nagesh Sankaran ◽  
THIRUMANAVELAN GANDHI
Keyword(s):  
Natural Products ◽  
Transition Metal ◽  
Bond Activation ◽  
Bioactive Molecules ◽  
Structural Motifs ◽  
The Past ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Phthalazinones and their higher congeners are commonly prevalent structural motifs that occur in natural products, bioactive molecules, and pharmaceuticals. In the past few decades transition metal-catalyzed reactions have received an...

Monodentate Trialkylphosphines: Privileged Ligands in Metal-catalyzed Crosscoupling Reactions

2020 ◽  
Vol 24 (3) ◽  
pp. 231-264 ◽  
Author(s):  
Kevin H. Shaughnessy
Keyword(s):  
Transition Metal ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Wide Range ◽  
Sterically Demanding ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Phosphines are widely used ligands in transition metal-catalyzed reactions. Arylphosphines, such as triphenylphosphine, were among the first phosphines to show broad utility in catalysis. Beginning in the late 1990s, sterically demanding and electronrich trialkylphosphines began to receive attention as supporting ligands. These ligands were found to be particularly effective at promoting oxidative addition in cross-coupling of aryl halides. With electron-rich, sterically demanding ligands, such as tri-tertbutylphosphine, coupling of aryl bromides could be achieved at room temperature. More importantly, the less reactive, but more broadly available, aryl chlorides became accessible substrates. Tri-tert-butylphosphine has become a privileged ligand that has found application in a wide range of late transition-metal catalyzed coupling reactions. This success has led to the use of numerous monodentate trialkylphosphines in cross-coupling reactions. This review will discuss the general properties and features of monodentate trialkylphosphines and their application in cross-coupling reactions of C–X and C–H bonds.

Chemistry of Unsymmetrical C1-Substituted Oxabenzonorbornadienes

2021 ◽  
Vol 17 ◽  
Author(s):  
Austin Pounder ◽  
Angel Ho ◽  
Matthew Macleod ◽  
William Tam
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Substituent Effects ◽  
Face Selectivity ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Synthetic Intermediate

: Oxabenzonorbornadiene (OBD) is a useful synthetic intermediate which can be readily activated by transition metal complexes with great face selectivity due to its dual-faced nature and intrinsic angle strain on the alkene. To date, the understanding of transition-metal catalyzed reactions of OBD itself has burgeoned; however, this has not been the case for unsymmetrical OBDs. Throughout the development of these reactions, the nature of C1-substituent has proven to have a profound effect on both the reactivity and selectivity of the outcome of the reaction. Upon substitution, different modes of reactivity arise, contributing to the possibility of multiple stereo-, regio-, and in extreme cases, constitutional isomers which can provide unique means of constructing a variety of synthetically useful cyclic frameworks. To maximize selectivity, an understanding of bridgehead substituent effects is crucial. To that end, this review outlines hitherto reported examples of bridgehead substituent effects on the chemistry of unsymmetrical C1-substituted OBDs.

Recent advance in NHC-palladium catalysis for alkynes chemistry: versatile synthesis and applications

2021 ◽  
Author(s):  
Jianxiao Li ◽  
Dan He ◽  
Zidong Lin ◽  
Wanqing Wu ◽  
Huanfeng Jiang
Keyword(s):  
Transition Metal ◽  
Palladium Catalysis ◽  
Metal Catalysts ◽  
Chemical Transformations ◽  
The Past ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

During the past decades, alkynes chemistry has attracted considerable attention owing to their unique and idiographic nucleophilic and electrophilic properties in transition-metal-catalyzed chemical transformations. Among the various metal catalysts, palladium...

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