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Flash Communication: Ti-Catalyzed "Interrupted" Cascading Hydroamination of 1,6- and 1,7-En-ynes
Kathryn J Rynders1, Daniel N Huh1, Zoe E Stuart1
1Department of Chemistry, University of Minnesota-Twin Cities, 207 Pleasant St SE, Minneapolis MN 55455.
A novel titanium imido precatalyst enables hydroaminative cyclization of en-ynes. This reaction forms α-carbocyclic imines via cascading C-N and C-C bond formation, offering a new synthetic route.
Area of Science:
- Organometallic Chemistry
- Synthetic Organic Chemistry
- Catalysis
Background:
- Hydroamination reactions are crucial for C-N bond formation.
- Titanium imido complexes are known to react with alkynes via [2+2] cycloaddition.
Purpose of the Study:
- To develop a new hydroaminative cyclization method for 1,6- and 1,7-en-ynes.
- To utilize a simple titanium imido precatalyst for this transformation.
Main Methods:
- Employing a titanium imido precatalyst, [py2TiCl2(NPh)]2.
- Interception of the azatitanacyclobutadiene intermediate with tethered alkenes.
- Protonolysis of the resulting metallacycle.
Main Results:
- Successful hydroaminative cyclization of 1,6- and 1,7-en-ynes.
- Formation of α-carbocyclic imine products.
- Demonstration of cascading C-N and C-C bond formation.
Conclusions:
- The developed method provides an efficient route to α-carbocyclic imines.
- The titanium imido precatalyst facilitates a cascade process involving cyclization and insertion.
- This work expands the utility of titanium imido complexes in organic synthesis.
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