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
Synthesis of diverse β-quaternary ketones via palladium-catalyzed asymmetric conjugate addition of arylboronic acids to cyclic enones
作者:Jeffrey C. Holder、Emmett D. Goodman、Kotaro Kikushima、Michele Gatti、Alexander N. Marziale、Brian M. Stoltz
DOI:10.1016/j.tet.2014.11.048
日期:2015.9
The development and optimization of a palladium-catalyzedasymmetricconjugateaddition of arylboronicacids to cyclic enone conjugateacceptors is described. These reactions employ air-stable and readily-available reagents in an operationally simple and robust transformation that yields β-quaternary ketones in high yields and enantioselectivities. Notably, the reaction itself is highly tolerant of
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
Recoverable polystyrene-supported palladium catalyst for construction of all-carbon quaternary stereocenters via asymmetric 1,4-addition of arylboronic acids to cyclic enones
we describe the preparation of a recoverable polystyrene supported chiral palladium catalyst based on PyOx ligand suitable for asymmetric 1,4-addition of arylboronic acids to cyclic 3-substituted five- and six-memberedenones. In the reaction, all‑carbon quaternary stereocenters are formed with a high level of enantioselectivity (up to 91% ee) and conversion (up to 99%). The catalyst was used in 6 cycles
Palladium-Catalyzed Asymmetric Conjugate Addition of Arylboronic Acids to Five-, Six-, and Seven-Membered β-Substituted Cyclic Enones: Enantioselective Construction of All-Carbon Quaternary Stereocenters
作者:Kotaro Kikushima、Jeffrey C. Holder、Michele Gatti、Brian M. Stoltz
DOI:10.1021/ja200664x
日期:2011.5.11
The first enantioselective Pd-catalyzed construction of all-carbon quaternary stereocenters via 1,4-addition of arylboronic acids to β-substituted cyclic enones is reported. Reaction of a wide range of arylboronic acids and cyclic enones using a catalyst prepared from Pd(OCOCF(3))(2) and a chiral pyridinooxazoline ligand yields enantioenriched products bearing benzylic stereocenters. Notably, this