Polycyclic Indoline-Benzodiazepines through Electrophilic Additions of α-Imino Carbenes to Tröger Bases
Alessandro Bosmani1, Alejandro Guarnieri-Ibáñez1, Sébastien Goudedranche1
1Département de Chimie Organique, Université de Genève, quai Ernest Ansermet 30, 1211, Geneva 4, Switzerland.
Abstract:
Polycyclic indoline-benzodiazepines can be accessed through the intermolecular reaction of Tröger bases with N-sulfonyl-1,2,3-triazoles. Under RhII catalysis, α-imino carbenes are generated and a subsequent cascade of [1,2]-Stevens, Friedel-Crafts, Grob, and aminal formation reactions yield the polycyclic heterocycles as single isomers (d.r.>49:1, four stereocenters including two bridgehead N atoms). Further ring expansion by insertion of a second α-imino carbene leads to elaborated polycyclic 9-membered-ring triazonanes.
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