手性铜( II )络合物催化丙二酸酯对β,γ-不饱和-α-酮酯的对映选择性迈克尔加成反应,实现了高产率(高达96%)和高ee(高达92%) 。手性配体同时利用了联萘基和脯氨酸部分,并且可以容忍具有不同电子和空间特征的取代基。反应可以在温和的条件下进行,并且可以在不损失产率和对映选择性的情况下实现克级反应。
A new ring for your indole: An unprecedented copper‐catalyzed enantioselectiveFriedel–Craftsalkylation/N‐hemiacetalization cascade reaction with indoles and β,γ‐unsaturated α‐ketoesters is reported. This mild strategy provides new access to various synthetically and biologically important 2,3‐dihydro‐1H‐pyrrolo[1,2‐a]indoles in a highlyenantioselective manner.
吲哚的新环:据报道,铜与吲哚和β,γ-不饱和α-酮酸酯发生了前所未有的铜催化对映选择性Friedel-Crafts烷基化/ N-半缩醛化级联反应。这种温和的策略以高度对映选择性的方式为各种合成和生物学上重要的2,3-二氢-1 H-吡咯并[1,2- a ]吲哚提供了新途径。
Highly Enantioselective Nickel-Catalyzed Oxa-[3+3]-annulation of Phenols with Benzylidene Pyruvates for Chiral Chromans
作者:Hai Ren、Xiang-Yang Song、Sunewang R. Wang、Lijia Wang、Yong Tang
DOI:10.1021/acs.orglett.8b01442
日期:2018.7.6
Nickel-catalyzed asymmetric annulation of oxygenated phenols and previously challenging 3-aminophenols with β,γ-unsaturated α-ketoesters is described, leading to rapid access to a variety of oxygenated and 7-aminated chromans in excellent yields with excellent diastereoselectivities and enantioselectivities under mild conditions. This method was readily scaled-up to gram scale and applied for a concise
A highlyenantioselective Michael addition of allomaltol (5‐hydroxy‐2‐methyl‐4H‐pyran‐4‐one) to both aromatic and aliphatic β,γ‐unsaturated α‐ketoesters has been realized. Under the catalysis of a chiral bifunctional tertiary amine‐squaramide that bears a (1R,2R)‐1,2‐diphenylethane‐1,2‐diamine scaffold, the reaction proceeded smoothly with high levels of enantioselectivity to give the desired products
Michael Addition–Lactonization of Arylacetyl Phosphonate to β,γ-Unsaturated α-Keto Esters for the Synthesis of Chiral <i>syn</i>-3,4-Dihydropyranones and 5,6-Dihydropyranones
Catalytic asymmetric Michael addition–lactonization of arylacetyl phosphonates to β,γ-unsaturated α-ketoesters by a chiral bifunctional thiourea–tertiary amine was established. Using the developed protocol, a range of optically pure syn-3,4-dihydropyranones were generated in good yields with good to excellent stereoselectivities (up to >20:1 dr and 99% ee). Meanwhile, when stoichiometric diisopropylethylamine