Convenient Titanium(III)-Catalyzed Synthesis of Cyclic Aminoketones and Pyrrolidinones—Development of a Formal [4+1] Cycloaddition


  • We thank Dr. Nils Trapp for the X-ray analysis and the Fonds der Chemischen Industrie and the Deutsche Forschungsgemeinschaft (DFG) for financial support.


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Have it both ways: α-Aminated ketones can be prepared by the titanium(III)-catalyzed reductive radical cyclization of iminonitriles. Depending on the position of the nitrile at the imine carbon or nitrogen, cyclic aminoketones or pyrrolidin-3-ones with a tetrasubstituted α-carbon can be formed in up to quantitative yield. In the latter case, the imine condensation and TiIII catalysis correspond to a formal [4+1] cycloaddition.