Reactions of thermally generated benzynes with diaziridines are reported. These trapping reactions follow the same pathway as reported earlier by Heine and co-workers with electron-deficient alkynes. The resulting N-arylhydrazones were obtained efficiently in a single step. The preference for the mode of addition of the nucleophilic diaziridine nitrogen atom to the more electrophilic benzyne carbon was consistent with what is predicted on the basis of distortion analysis. The feasibility of converting the hydrazone into a Fisher-indole adduct was demonstrated.
Bibliographical noteFunding Information:
The help of Mr. Ramitha Rupasinghe with some of the early experiments aimed at preparation of diaziridines is appreciated. Support for this research was provided by the National Institutes of General Medical Sciences of the U.S. Department of Health and Human Services (R01 GM65597, then R35 GM127097). A portion of the NMR spectral data was acquired with an instrument purchased with funds provided by the NIH Shared Instrumentation Grant program (S10OD011952). DFT calculations were performed with hardware and software resources made available through the Minnesota Supercomputer Institute.