Design of a Small-Molecule Catalyst Using Intramolecular Cation−π Interactions for Enantioselective Diels−Alder and Mukaiyama−Michael Reactions: <scp>l</scp>-DOPA-Derived Monopeptide·Cu(II) Complex
作者:Kazuaki Ishihara、Makoto Fushimi
DOI:10.1021/ol060651l
日期:2006.4.1
[reaction: see text] We have designed a small-molecule artificial metalloenzyme that is prepared in situ from Cu(OTf)(2) or Cu(NTf(2))(2) (1.0 equiv) and l-DOPA-derived monopeptide (1.1 equiv). This catalyst (2-10 mol %) is highly effective for the enantioselectiveDiels-Alder (DA) and Mukaiyama-Michael (MM) reactions with alpha,beta-unsaturated 1-acyl-3,5-dimethylpyrazoles. The present results demonstrate
catalyzes the enantioselective1,3-dipolarcycloaddition reaction of nitrones with propioloylpyrazole and acryloylpyrazole derivatives. The asymmetric environment created by intramolecular π-cation interaction gives the corresponding adducts in high yields with excellent enantioselectivity. This is the first successful method for the catalytic enantioselective1,3-dipolarcycloaddition of nitrones with acetylene
3-(2-萘基)-l-丙氨酸酰胺的手性铜 (II) 配合物成功催化硝酮与丙炔基吡唑和丙烯酰吡唑衍生物的对映选择性 1,3-偶极环加成反应。由分子内 π-阳离子相互作用产生的不对称环境以高产率提供相应的加合物,并具有出色的对映选择性。这是硝酮与乙炔衍生物的催化对映选择性 1,3-偶极环加成反应的第一个成功方法。1,3-偶极环加合物可以通过使用 SmI(2) 还原裂解 NO 键而立体选择性地转化为 β-内酰胺。
Double catalytic enantioselective Michael addition reactions of tertiary nucleophile precursors—tertiary/quaternary and quaternary/quaternary carbon–carbon bond formations
Enantioselective Michael addition reactions of tertiary nucleophile precursors, such as substituted malononitriles and cyclic 1,3-diketones, can be successfully activated by the metal complexes derived from R,R-DBFOX/Ph chiral ligand and cationic metal salts. With this method, the enantioselective tertiary/quaternary and quaternary/quaternary carbon–carbon bond formations can be achieved. Use of alcohol
Molecular sieves 4A work to mediate the catalytic metal enolization of nucleophile precursors: application to catalyzed enantioselective Michael addition reactions
作者:Masayuki Hasegawa、Fumiyasu Ono、Shuji Kanemasa
DOI:10.1016/j.tetlet.2008.05.156
日期:2008.8
Molecular sieves 4A (MS4A) work effectively as base leading to catalytic generation of nickel(II) enolate or nitronate nucleophiles through deprotonation of the α-hydrogen atom of nucleophile precursors on treatment with a catalytic amount of chiral nickel(II) ions. The resulting reactive intermediates can be successfully trapped with α,β-unsaturated carbonyl electrophiles to produce the corresponding
Thorpe–Ingold Effect on High-Performance Chiral π–Copper(II) Catalyst
作者:Kazuaki Ishihara、Kazuki Nishimura
DOI:10.1055/a-1750-8481
日期:2022.4
The Thorpe–Ingold effect was applied to the design of a chiral ligand of π–copper(II) catalysts for the enantioselective α-fluorination of N-acyl-3,5-dimethylpyrazoles, and also for the enantioselective Mukaiyama–Michael, Diels–Alder, and 1,3-dipolar cycloaddition reactions of N-acryloyl-3,5-dimethylpyrazoles. The use of β,β-dimethyl-β-arylalanine-type ligand gave desired products with higher enantioselectivity