Reaction of ethyl acylindole-2-carboxylates with thallium trinitrate (synthetic studies on indoles and related compounds. XXXIII)
Ethyl acylindole-2-carboxylates were treated with thallium trinitrate (TTN) in methanol, methyl orthoformate, methyl orthoformate/sulfuric acid, and acetic acid. The reactions in the former three methanolic solvents gave methyl indoleacetate derivatives via the Favorskii-type rearrangement reaction at the acyl group, whereas the reaction in acetic acid gave oxindole derivative with rearrangement of the C2-ethoxycarbonyl group. The TTN reaction was applied to a model compound leading to the synthesis of lysergic acid.
Efficient synthesis of t-butyl 3-alkyl-N-hydroxy-oxindole-3-carboxylates from di-t-butyl 2-nitrophenylmalonates
– A selective and efficient synthesis of t-butyl 3-alkyl-N-hydroxy-oxindole-3-carboxylates from di-t-butyl 2-nitrophenylmalonates is described. A tandem reduction-cyclization approach involving reduction of di-t-butyl 2-methyl-(2-nitrophenyl)malonate to d
Synthesis of Quaternary 3,3-Disubstituted 2-Oxindoles from 2-Substituted Indole Using Selectfluor
A facile method to construct quaternary 3,3-disubstituted 2-oxindole from 2-substituted indole without a catalyst in mild conditions is developed. A mechanistic study suggests that an iminium-intermediate-triggered 1,2-rearrangement is involved, and a tra