2002
Conformational studies on indole alkaloids from Flustra foliacea by NMR and molecular modeling. Morales-Ríos Martha S., Santos-Sánchez Norma F., Suárez-Castillo Oscar R. DOI: 10.1002/mrc.1080
Abstract
1H and 13C NMR assignments for 1a4a and 1b4b were obtained using HSQC, HMBC and NOESY techniques. Differences and ambiguities from literature assignments are reconciled. For the pyrrolidine C-ring, the combined use of NMR spectroscopy and molecular mechanics calculations revealed that this ring exists in a dynamic conformational equilibrium between twist (2T1) and envelope-twist (1E1T2) conformations. In chloroform-d1, the 1H NMR coupling constants indicate that the pyrrolidine ring is biased in favor of the envelope-twist conformation. Steric requirements of the N-prenyl group enhanced the envelope-twist (1E1T2) conformation populations.
Transesterifications mediated by t-BuNH2
The absoluteconfiguration of cuauhtemone and related compounds
13C NMR and crystallographic evidence of push-pull effects in furoindolic ?-enamino esters
Synthesis of Indolylindolines Mediated by tert-BuNH2
Absolute configuration determination of 2-(2-oxo-3-indolyl)acetamide derivatives
Aromatic Bromination versus Oxidation of Indolylmalonates by Bromine