The Cinchona Primary Amine-Catalyzed Asymmetric Epoxidation and Hydroperoxidation of α,β-Unsaturated Carbonyl Compounds with Hydrogen Peroxide
作者:Olga Lifchits、Manuel Mahlau、Corinna M. Reisinger、Anna Lee、Christophe Farès、Iakov Polyak、Gopinadhanpillai Gopakumar、Walter Thiel、Benjamin List
DOI:10.1021/ja402058v
日期:2013.5.1
Using cinchona alkaloid-derived primary amines as catalysts and aqueous hydrogenperoxide as the oxidant, we have developed highly enantioselective Weitz-Scheffer-type epoxidation and hydroperoxidation reactions of α,β-unsaturated carbonylcompounds (up to 99.5:0.5 er). In this article, we present our full studies on this family of reactions, employing acyclic enones, 5-15-membered cyclic enones, and
A General, Scalable, Organocatalytic Nitro-Michael Addition to Enones: Enantioselective Access to All-Carbon Quaternary Stereocenters
作者:Xiaodong Gu、Yuanyuan Dai、Tingting Guo、Allegra Franchino、Darren J. Dixon、Jinxing Ye
DOI:10.1021/acs.orglett.5b00387
日期:2015.3.20
Michael addition of nitromethane to five-, six-, and seven-membered β-substituted cyclic enones with excellent enantioselectivity, offering scalable, asymmetric access to all-carbon quaternary stereocenters. The reaction scope can be expanded to include linear acyclic enones, and excellent levels of enantioselectivity are also observed. Furthermore, this organocatalytic, asymmetric nitro-Michael reaction
Synthesis of <i>N</i>-substituted quaternary carbon centers through KO<i>t</i>-Bu-catalyzed aza-Michael addition of pyrazoles to cyclic enones
作者:Subin Yoon、Sungbin Lee、Seung Hyun Nam、Hyejeong Lee、Yunmi Lee
DOI:10.1039/d2ob01634f
日期:——
This study reports an efficient and mild method for the synthesis of cyclic β-amino ketones containing N-substituted quaternary carbon centers via the KOt-Bu-catalyzed aza-Michael addition reaction of pyrazoles to β-substituted cyclic α,β-enones. The amination was promoted by KOt-Bu (3 mol%) at ambient temperature and a wide range of new and versatile β-pyrazolyl ketones were obtained in good yields
本研究报告了一种高效且温和的方法,通过KO t -Bu 催化的吡唑与β-取代的环状α、β-烯酮的氮杂-迈克尔加成反应,合成含有N-取代季碳中心的环状β-氨基酮。在环境温度下通过 KO t -Bu (3 mol%)促进胺化,并以良好的产率获得了范围广泛的新型多功能β-吡唑基酮。此外,KO t -Bu 催化的环状二烯酮与吡唑的一锅二聚反应通过还探索了 aza-1,6-共轭加法,然后是 aza-1,4-共轭加法。