RESUMEN
A convenient and efficient approach for the difunctionalization of alkenylpyridine N-oxides through the tandem addition/Boekelheide rearrangement has been developed. The C-O and C-X (S, O, Cl) bonds are constructed simultaneously at the α- and ß-positions under mild reaction conditions in 100% atom economy, which complements previously reported α- or ß-functionalizations.
RESUMEN
An efficient regioselective sp3 C-H azidation is developed using CuBr as the catalyst and Zhdankin azidoiodinane as the "N3" source. Under simple and mild reaction conditions, the azido group could be successfully incorporated into the sp3 C-H alkyl substituents of indoles and tetrahydrocarbazoles.
RESUMEN
Enantioselective synthesis of imidazolidin-5-ones through a phosphoric acid catalyzed reaction between azlactones and N-substituted ß-carbolines is reported. The reaction takes place via an initial formal [2+2] cycloaddition to generate an α-amino-ß-lactam, which subsequently undergoes an acid-catalyzed asymmetric penicillin-penillonic acid (PPA) rearrangement with high diastereo- and enantioselectivity. To the best of our knowledge, this represents the first [2+2] cyclization of azlactones with imines and the first asymmetric PPA rearrangement, which are linked together by the phosphoric acid catalyst.