Enantioselective Intermolecular C–H Amination Directed by a Chiral Cation
作者:Alexander Fanourakis、Benjamin D. Williams、Kieran J. Paterson、Robert J. Phipps
DOI:10.1021/jacs.1c05206
日期:2021.7.14
The enantioselective amination of C(sp3)–H bonds is a powerful synthetic transformation yet highly challenging to achieve in an intermolecular sense. We have developed a family of anionic variants of the best-in-class catalyst for Rh-catalyzedC–Hamination, Rh2(esp)2, with which we have associated chiral cations derived from quaternized cinchona alkaloids. These ion-paired catalysts enable high levels
A convergent approach to (R)-Tiagabine by a regio- and stereocontrolled hydroiodination of alkynes
作者:Giuseppe Bartoli、Roberto Cipolletti、Giustino Di Antonio、Riccardo Giovannini、Silvia Lanari、Mauro Marcolini、Enrico Marcantoni
DOI:10.1039/c005042c
日期:——
The occurrence of unsaturated systems in natural products combined with the mildness and the wide range of applicability of CeCl3 promoted methodologies suggest several potential future synthetic applications within the field of total synthesis of biologically active molecules. On this concept, the use of CeCl3·7H2O–NaI system as an efficient heterogeneous promoter has been highlighted in the iodofunctionalization of carbon–carbon triple bonds. The study has shown that this method would be particularly interesting for the stereoselective formation of trisubstituted (Z)- or (E)-iodoalkenes by simply changing the nature of the solvent. The methodology has been successfully applied to the synthesis of (R)-1-[4,4-bis-(3-methyl-2-thienyl)-3-butenyl]-3-piperidinecarboxylic acid 1, named (R)-Tiagabine, which is a potent and selective γ-aminobutyric acid (GABA) uptake inhibitor with proven anticonvulsant efficacy in humans.