A Two-Component Alkyne Metathesis Catalyst System with an Improved Substrate Scope and Functional Group Tolerance: Development and Applications to Natural Product Synthesis

2016 ◽  
Vol 22 (25) ◽  
pp. 8494-8507 ◽  
Author(s):  
Sebastian Schaubach ◽  
Konrad Gebauer ◽  
Felix Ungeheuer ◽  
Laura Hoffmeister ◽  
Marina K. Ilg ◽  
...  
Keyword(s):  
Natural Product ◽  
Functional Group ◽  
Catalyst System ◽  
Natural Product Synthesis ◽  
Alkyne Metathesis ◽  
Tolerance Development ◽  
Metathesis Catalyst ◽  
Two Component

Arylene–ethynylene macrocycles: Privileged shape-persistent building blocks for organic materials

2012 ◽  
Vol 84 (4) ◽  
pp. 869-878 ◽  
Author(s):  
Dustin E. Gross ◽  
Ling Zang ◽  
Jeffrey S. Moore
Keyword(s):  
Functional Group ◽  
Organic Materials ◽  
Building Blocks ◽  
Alkyne Metathesis ◽  
Reaction Conditions ◽  
Traditional Methods ◽  
Dynamic Covalent Chemistry ◽  
Highly Active ◽  
Recent Advances ◽  
Metathesis Catalyst

This report details the advances in synthetic strategies toward arylene–ethynylene macrocycles (AEMs). After a brief description of traditional methods, we summarize recent advances based on dynamic covalent chemistry (DCC) whereby a highly active and functional group tolerant alkyne metathesis catalyst yields scalable quantities of AEMs under thermodynamic controlled reaction conditions.

scholarly journals Highly active alkyne metathesis catalysts operating under open air condition

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanqing Ge ◽  
Shaofeng Huang ◽  
Yiming Hu ◽  
Lei Zhang ◽  
Ling He ◽  
...  
Keyword(s):  
Catalyst System ◽  
Alkyne Metathesis ◽  
Ambient Conditions ◽  
High Moisture ◽  
Highly Active ◽  
Active User ◽  
Metathesis Catalyst ◽  
Cyano Groups ◽  
Metathesis Catalysts ◽  
User Friendly

AbstractAlkyne metathesis represents a rapidly emerging synthetic method that has shown great potential in small molecule and polymer synthesis. However, its practical use has been impeded by the limited availability of user-friendly catalysts and their generally high moisture/air sensitivity. Herein, we report an alkyne metathesis catalyst system that can operate under open-air conditions with a broad substrate scope and excellent yields. These catalysts are composed of simple multidentate tris(2-hydroxyphenyl)methane ligands, which can be easily prepared in multi-gram scale. The catalyst substituted with electron withdrawing cyano groups exhibits the highest activity at room temperature with excellent functional group tolerance (-OH, -CHO, -NO2, pyridyl). More importantly, the catalyst provides excellent yields (typically >90%) in open air, comparable to those operating under argon. When dispersed in paraffin wax, the active catalyst can be stored on a benchtop under ambient conditions without any decrease in activity for one day (retain 88% after 3 days). This work opens many possibilities for developing highly active user-friendly alkyne metathesis catalysts that can function in open air.

scholarly journals Catalytic, contra-Thermodynamic Alkene Isomerization

2021 ◽  
Author(s):  
Gino Occhialini ◽  
Vignesh Palani ◽  
Alison Wendlandt
Keyword(s):  
Natural Product ◽  
Catalyst System ◽  
Natural Product Synthesis ◽  
Mechanistic Studies ◽  
Double Bonds ◽  
Positional Isomerization ◽  
Alkene Isomerization ◽  
Terminal Alkene ◽  
Homolytic Substitution ◽  
Powerful Strategy

The positional isomerization of C–C double bonds is a powerful strategy for the interconversion of alkene regioisomers. However, existing methods provide access to thermodynamically more stable isomers from less stable starting materials. Here we report the discovery of a dual catalyst system that promotes contra-thermodynamic positional alkene isomerization under photochemical irradiation, providing access to terminal alkene isomers directly from conjugated, internal alkene starting materials. The utility of the method is demonstrated in the deconjugation of diverse electron rich/poor alkenes and through strategic application to natural product synthesis. Mechanistic studies are consistent with a regiospecific bimolecular homolytic substitution (SH2') mechanism proceeding through an allyl-cobaloxime intermediate.

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