Synthesis with Perfect Atom Economy: Generation of Diazo Ketones by 1,3-Dipolar Cycloaddition of Nitrous Oxide at Cyclic Alkynes under Mild Conditions


  • We gratefully acknowledge financial support from the Deutsche Forschungsgemeinschaft (BA 903/10-3). O.P. thanks the Studentenwerk Chemnitz–Zwickau for a fellowship of the Freistaat Sachsen. We are grateful to Dr. M. Hagedorn for experimental support and assistance with the manuscript. Prof. A. Krebs and Prof. H. Detert gave us highly useful tips for the synthesis of cycloalkynes. We thank Prof. M. Oestreich for support with the MS experiments. Strained Rings, Part 2; for Part 1, see: M. Al-Omari, K. Banert, M. Hagedorn, Angew. Chem.2006, 118, 315–317; Angew. Chem. Int. Ed.2006, 45, 309–311.


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A cascade of five steps, transforms cyclooctynes in the presence of nucleophiles NuH and nitrous oxide, into the depicted products (see scheme). In another example, nitrous oxide was added at a cycloalkyne at −25 °C to generate the corresponding diazo ketone. In both cases, all three atoms of nitrous oxide were incorporated into the products.