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Copper(i)-catalysed transfer hydrogenations with ammonia borane
Eva Korytiaková1, Niklas O Thiel1, Felix Pape1
1Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany. johannes.teichert@chem.tu-berlin.de.
A copper(I)/N-heterocyclic carbene complex enables highly Z-selective alkyne semihydrogenations and conjugate hydrogenations using ammonia borane as a hydrogen source.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Organic Synthesis
Background:
- Copper catalysis is crucial for various organic transformations.
- N-heterocyclic carbenes (NHCs) are versatile ligands in organometallic chemistry.
- Efficient and selective hydrogenation methods are essential in synthetic chemistry.
Purpose of the Study:
- To develop a highly Z-selective method for alkyne semihydrogenation.
- To achieve conjugate transfer hydrogenation of enoates.
- To utilize a stable and accessible copper catalyst with ammonia borane as the hydrogen source.
Main Methods:
- Employing a readily available and air-stable copper(I)/N-heterocyclic carbene (NHC) complex, specifically [IPrCuOH].
- Utilizing ammonia borane (H3NBH3) as a convenient and recyclable H2 source.
- Performing catalytic transfer hydrogenation reactions under mild conditions.
Main Results:
- Achieved highly Z-selective alkyne transfer semihydrogenations.
- Successfully demonstrated conjugate transfer hydrogenation of enoates.
- The copper(I)/NHC complex proved effective and stable under the reaction conditions.
Conclusions:
- The developed catalytic system offers an efficient route to Z-alkenes and saturated esters.
- Ammonia borane serves as a practical hydrogen source for these transformations.
- This method provides a valuable tool for selective organic synthesis.
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