910117-03-2Relevant academic research and scientific papers
Studies on gold(i) and gold(iii) alcohol functionalised NHC complexes
Jónsson, Helgi Freyr,Orthaber, Andreas,Fiksdahl, Anne
, p. 5128 - 5138 (2021/04/26)
Five pairs of novel chiral alcohol functionalised gold(i) and gold(iii) NHC complexes derived from chiral amino alcohols, were synthesized and characterised (NMR, IR, HRMS). Single crystal X-ray diffraction data of gold(i) and gold(iii) complexes are reported and discussed. The chiral imidazolium preligands were readily synthesizedviathe oxalamides, subsequent reduction and final orthoformate condensation. An improved method was used for generation of gold(i) NHC complexes (up to 92%) and further oxidation afforded the corresponding gold(iii) NHC complexes (up to 99%). All the Au(i) and Au(iii) NHC complexes proved far more catalytically active in a 1,6-enyne alkoxycyclization test reaction than our previously testedN,N- andP,N-ligated Au(iii) complexes. Comparative gold(i) and gold(iii) catalytic studies demonstrated different catalytic ability, depending on the NHC ligand flexibility and bulkiness. Excellent yields (92-99%) of target alkoxycyclization product were obtained with both gold(i) and gold(iii) complexes with the bulkyN1-Mes-N2-ethanol based NHC ligand.
Synthesis and crystallographic characterization of chiral bis-oxazoline-amides. Fine-tunable ligands for Pd-catalyzed asymmetric alkylations
Albano, Vincenzo Giulio,Bandini, Marco,Monari, Magda,Marcucci, Eleonora,Piccinelli, Fabio,Umani-Ronchi, Achille
, p. 6451 - 6458 (2007/10/03)
New chiral chelating C2 bis-oxazoline-amide ligands (1) exhibiting a highly flexible molecular structure have been prepared in high yield through a versatile synthetic pathway. Combined crystallographic, variable temperature (VT)-NMR, IR, and ESI-MS studies have been carried out to investigate the nature of the 1-Pd complexes that are effective tools in controlling the stereochemical outcome of Pd-catalyzed allylic alkylations (ee up to 98%).
Design and synthesis of new bidentate alkoxy-NHC ligands for enantioselective copper-catalyzed conjugate addition
Clavier, Hervé,Coutable, Ludovic,Toupet, Lo?c,Guillemin, Jean-Claude,Mauduit, Marc
, p. 5237 - 5254 (2007/10/03)
A new family of chiral alkoxy-N-heterocyclic carbene (NHC) ligands has been designed for the enantioselective copper-catalyzed conjugate addition of dialkylzincs to enones. These new bidentate NHC ligands were synthesized in high overall yields using a five-step procedure starting from commercially available β-aminoalcohols. Influence of the temperature, base, solvent and copper source were studied in order to optimize the stereoselectivity of the addition. High reactivity and excellent enantioselectivity were obtained at ambient temperature with a range of cyclic enones and dialkylzinc. Addition to acyclic enones has also been studied.
