Reactions of Diaziridines with Benzynes Give N‑Arylhydrazones

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Arora, S.; Palani, V.; Hoye, T. R. Org. Lett. 201820, 8082–8085.

This manuscript is dedicated in memory of Professor Harold W. Heine, formerly of Bucknell University, and in recognition of his considerable scientific and mentoring legacy, which has so positively impacted so many (including the outgoing Editor-in-Chief of Organic Letters).

Abstract

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.