Transition-Metal catalyzed sp3-C-H Bond Amination from Aryl Azides
thesisposted on 27.02.2015, 00:00 authored by Quyen T. Nguyen
This thesis studied transition metal catalyzed sp3-C–H amination reaction using aryl azides as the nitrogen source to produce N-heterocyclic compounds including indole and indoline. First, Rh2(esp)2 mediated aliphatic C−H bond amination reactions of aryl azides without requiring a strong electron-withdrawing group on the nitrogen atom was presented. The mechanistic study carried out on the reactivity of stereospecific labeled aryl azides supported for the formation of the nitrenoid followed by stepwise pathway with the syn-C−H bond through radical species. Second, the tandem ethereal C−H bond amination−elimination-[1,2]-migration reaction catalyzed by inexpensive, nontoxic FeBr2 was discussed. With the successful isolation of some intermediates, mechanistic experiments revealed FeBr2 to be essential for both the C–H bond amination as well as the iminium ion generation. Finally, dirhodium(II) carboxylate promoting the formation of 1,2,3-trisubstituted indoles from styryl azides was investigated. The proposed mechanism involved 4π-electron-5-atom electrocyclization and formation of spirocyclic cation that triggers the migration process.