Redox‐active BIAN‐based Diimine Ligands in Metal‐Catalyzed Small Molecule Syntheses

The use of dad (and bian) ligands in the stabilization of main-group complexes, in particular metal–metal-bonded compounds, as well as the small molecule reactivity of these (low-valent) metal complexes, is summarized.

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Interactions between tetrathiafulvalene units in dimeric structures – the influence of cyclic cores

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.11.104 ◽

2015 ◽

Vol 11 ◽

pp. 930-948 ◽

Cited By ~ 7

Author(s):

Huixin Jiang ◽

Virginia Mazzanti ◽

Christian R Parker ◽

Søren Lindbæk Broman ◽

Jens Heide Wallberg ◽

...

Keyword(s):

Cyclic Voltammetry ◽

Coupling Reactions ◽

Double Bonds ◽

Redox Active ◽

Metal Catalyzed ◽

Selection Of

A selection of cyclic and acyclic acetylenic scaffolds bearing two tetrathiafulvalene (TTF) units was prepared by different metal-catalyzed coupling reactions. The bridge separating the two TTF units was systematically changed from linearly conjugated ethyne, butadiyne and tetraethynylethene (trans-substituted) units to a cross-conjugated tetraethynylethene unit, placed in either acyclic or cyclic arrangements. The cyclic structures correspond to so-called radiaannulenes having both endo- and exocyclic double bonds. Interactions between two redox-active TTF units in these molecules were investigated by cyclic voltammetry, UV–vis–NIR and EPR absorption spectroscopical methods of the electrochemically generated oxidized species. The electron-accepting properties of the acetylenic cores were also investigated electrochemically.

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Recent Advances in Piperazine Synthesis

Synthesis ◽

10.1055/s-0036-1589491 ◽

2017 ◽

Vol 49 (12) ◽

pp. 2589-2604 ◽

Cited By ~ 33

Author(s):

Kristen Gettys ◽

Zhishi Ye ◽

Mingji Dai

Keyword(s):

Transition Metal ◽

Small Molecule ◽

Ring System ◽

Reductive Cyclization ◽

The Third ◽

Methods Development ◽

Recent Advances ◽

Borrowing Hydrogen ◽

Palladium Catalyzed ◽

Metal Catalyzed

Piperazine ranks as the third most common N-heterocycle appearing in small-molecule pharmaceuticals. This review highlights recent advances in methods development for the construction of the piperazine ring system with particular emphasis on preparing carbon-substituted piperazines.1 Introduction2 Reduction of (Di)ketopiperazine3 N-Alkylation4 Transition-Metal-Catalyzed/Mediated Piperazine Synthesis4.1 The SnAP and SLAP Methods4.2 Palladium-Catalyzed Cyclization4.3 Gold-Catalyzed Cyclization4.4 Other Metal-Catalyzed/Mediated Cyclization4.5 Borrowing Hydrogen Strategy4.6 Imine Reductive Cyclization5 Reduction of Pyrazines6 Miscellaneous7 Conclusion

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Opportunities and challenges for direct C–H functionalization of piperazines

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.12.70 ◽

2016 ◽

Vol 12 ◽

pp. 702-715 ◽

Cited By ~ 22

Author(s):

Zhishi Ye ◽

Kristen E Gettys ◽

Mingji Dai

Keyword(s):

Transition Metal ◽

Small Molecule ◽

Heterocyclic Compounds ◽

Structural Diversity ◽

Synthetic Methods ◽

Photoredox Catalysis ◽

Transition Metal Catalyzed ◽

Metal Catalyzed ◽

Nitrogen Heterocyclic

Piperazine ranks within the top three most utilized N-heterocyclic moieties in FDA-approved small-molecule pharmaceuticals. Herein we summarize the current synthetic methods available to perform C–H functionalization on piperazines in order to lend structural diversity to this privileged drug scaffold. Multiple approaches such as those involving α-lithiation trapping, transition-metal-catalyzed α-C–H functionalizations, and photoredox catalysis are discussed. We also highlight the difficulties experienced when successful methods for α-C–H functionalization of acyclic amines and saturated mono-nitrogen heterocyclic compounds (such as piperidines and pyrrolidines) were applied to piperazine substrates.

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