Catalytic asymmetric transformations with fine-tunable biphenol-based monodentate ligands
摘要:
A library of new fine-tunable monodentate phosphite and phosphoramidite ligands based on chiral biphenol have been designed and developed. These monodentate phosphorus ligands have exhibited excellent enantioselectivity in the Pd-catalyzed asymmetric allylic alkylation and Rh-catalyzed asymmetric hydrogenation. (c) 2006 Elsevier Ltd. All rights reserved.
Copper-Catalyzed Asymmetric Conjugate Addition of Trialkylaluminium Reagents to Trisubstituted Enones: Construction of Chiral Quaternary Centers
作者:Magali Vuagnoux-d'Augustin、Alexandre Alexakis
DOI:10.1002/chem.200701001
日期:2007.11.26
vinylalane species undergo enantioselective conjugateaddition to a wide range of 2- or 3-substituted enones (cyclopent-2-enones, cyclohex-2-enones, 3-methyl cyclohept-2-enone) in the presence of catalytic amount of copper salt (copper thiophene carboxylate, [Cu(CH3CN)4]BF4 or [CuOTf]2C6H6) and tropos-phosphoramidite-based ligand. Thus, chiral quaternarycenters can be built, with up to 98% ee after rigorous
Copper-Catalyzed Asymmetric Conjugate Addition with Chiral SimplePhos Ligands
作者:Laëtitia Palais、Alexandre Alexakis
DOI:10.1002/chem.200901577
日期:2009.10.12
they can be highly functionalised. Herein we report the copper‐catalysed asymmetricconjugateaddition of diethyl zinc and trialkylaluminium reagents with SimplePhos ligands, which gives high enantioselectivity with cyclic enones, acyclic enones and nitro‐olefins, with up to 98.6 % ee. Of particular interest is the reaction of trialkylaluminium reagents with a wide range of 3‐substituted enones, thus
Two successive asymmetric reductive aminations (ARAs) have been merged into one reaction system to generate enantiopure C2-symmetric secondary amines. The iridium-phosphoramidite complex successfully manages the dual ARAs by using two distinctly different types of amine sources: an inorganic ammonium salt and an organic primary amine.
Enantioselective Alkoxycyclization of 1,6‐Enynes with Gold(I)‐Cavitands: Total Synthesis of Mafaicheenamine C
作者:Inmaculada Martín‐Torres、Gala Ogalla、Jin‐Ming Yang、Antonia Rinaldi、Antonio M. Echavarren
DOI:10.1002/anie.202017035
日期:2021.4.19
cyclization has been applied for the first totalsynthesis of carbazole alkaloid (+)‐mafaicheenamine C and its enantiomer, establishing its configuration as R. The cavity effect was also evaluated in the cycloisomerization of dienynes. A combination of experiments and theoretical studies demonstrates that the cavity of the gold(I) complexes forces the enynes to adopt constrained conformations, which results
Readily available alkenylalanes, arising from hydroalumination of unprotected terminal alkynes, have been directly employed for the copper-catalyzedasymmetricconjugateaddition (ACA) to β-substituted cyclic enones. The desired products, containing a quaternary stereogenic center, are generally obtained in good yields and enantioselectivities.