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
Enantioselective Copper-Catalyzed Conjugate Addition to 2- or 3-Substituted Cyclopent-2-en-1-ones: Construction of Stereogenic Quaternary Carbon Centers
Trimethyl- and triethylaluminum undergo enantioselectiveconjugateaddition to 2- and 3-substituted cyclopent-2-en-1- ones in the presence of catalytic amount of a copper salt and a phosphoramidite or a diphosphite ligand. Thus, chiral quaternarycenters can be built with up to 93% ee.
在催化量的铜盐和亚磷酰胺或二亚磷酸酯配体的存在下,三甲基铝和三乙基铝经历对映选择性共轭加成到 2-和 3-取代的环戊-2-en-1-。因此,可以用高达 93% 的 ee 构建手性四元中心。
Formation of quaternary centres by copper catalysed asymmetric conjugate addition to β-substituted cyclopentenones with the aid of a quantitative structure–selectivity relationship
作者:Ruchuta Ardkhean、Mike Mortimore、Robert S. Paton、Stephen P. Fletcher
DOI:10.1039/c7sc05304e
日期:——
A new asymmetric conjugate addition method was developed for β-substituted cyclopentenones to form quaternary centres using alkylzirconocene nucleophiles giving up to 97% yield and 92% ee. Key to the reaction's success was the design of suitable phosphoramidite ligands which was aided by a linear quantitative structure–selectivityrelationship (QSSR). QSSR models were created from the ligand screening
Formation of Quaternary Chiral Centers by N-Heterocyclic Carbene-Cu-Catalyzed Asymmetric Conjugate Addition Reactions with Grignard Reagents on Trisubstituted Cyclic Enones
The copper‐catalyzedconjugateaddition of Grignard reagents to 3‐substituted cyclic enones allows the formation of all‐carbon chiral quaternary centers. We demonstrate in this article that N‐heterocyclic carbenes act as efficient chiral ligands for this transformation. High enantioselectivities (up to 96 % ee) could be obtained for a variety of substrates.
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