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A Straightforward Route to Helically Chiral N-Heteroaromatic Compounds: Practical Synthesis of Racemic 1,14-Diaza[5]helicene and Optically Pure 1- and 2-Aza[6]helicenes


  • This research was supported by the European Commission under Grant No. FP6-015847 and by the Grant Agency of the Czech Republic under Grant No. 203/06/1792.


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The taming of the screw: The CoI-catalyzed cyclotrimerization of triynes and microwave (MW) assisted aromatization with MnO2 are central to the practical synthesis of diaza[5]helicene and aza[6]helicenes. The aza[6]helicene racemates have been resolved, the absolute configuration of the enantiomers assigned, the energy barriers to racemization determined, and X-ray structures of their Ag complexes obtained (see picture; Cp=C5H5, OTf=triflate).