Room‐Temperature‐Stable Diazoalkenes by Diazo Transfer from Azides: Pyridine‐Derived Diazoalkenes

• Published in: Angewandte Chemie International Edition 2023-05, Vol.62 (19), p.e202301486-n/a
• Main Authors: Reitz, Justus, Antoni, Patrick W., Holstein, Julian J., Hansmann, Max M.
• Format: Article
• Language: English
• Subjects: Alkenes; Atmospheric chemistry; Azides (organic); Diazo Compounds; Diazoalkenes; Functional groups; Nitrogen Heterocycles; Nitrous oxide; Organic chemistry; Photochemicals; Pyridines; Reactive Intermediates; Vinylidenes
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202301486

Recently, stable diazoalkenes have received significant attention as a new substance class in organic chemistry. While their previous synthetic access was exclusively limited to the activation of nitrous oxide, we here establish a much more general synthetic approach utilizing a Regitz‐type diazo transfer with azides. Importantly, this approach is also applicable to weakly polarized olefins such as 2‐pyridine olefins. The new pyridine diazoalkenes are not accessible by the activation of nitrous oxide, allowing for a considerable extension of the scope of this only recently accessed functional group. The new diazoalkene class has properties distinct from the previously reported classes, such as photochemically triggered loss of dinitrogen affording cumulenes and not C−H insertion products. Pyridine‐derived diazoalkenes represent the so far least polarized stable diazoalkene class reported. Room‐temperature‐stable diazoalkenes based on a pyridine backbone are accessible via dinitrogen transfer from azides. This fundamentally new substance class features the lowest C−C bond polarization of the few known stable diazoalkenes, therefore representing best the presentation R2C=C=N2. Photochemically triggered loss of N2 represents a new strategy to access C4 cumulenes.