开发了一种用于合成手性四氢喹喔啉 (THQ) 衍生物的新型 Ir 催化不对称氢化方案。通过简单地调整反应溶剂,即可高产率地选择性地获得单取代手性 THQ 的两种对映体,且具有优异的对映选择性(甲苯/二恶烷:收率高达 93%,ee ( R ) 高达 98%;EtOH:收率高达 83%)和 93% ee ( S ))。对于2,3-二取代的手性THQ,获得的顺式氢化产物的收率高达95%,dr为20:1,ee为94%。值得注意的是,该方法也适用于连续流动条件下,产生具有相当收率和对映选择性的克级产品(二恶烷:91% 收率和 93% ee ( R );EtOH:90% 收率和 87% ee ( S ))。与之前报道的 Ir 催化不对称氢化方案不同,该系统表现出显着的改进,因为它不需要额外的添加剂。此外,还进行了全面的机理研究,包括氘标记实验、对照实验、动力学研究和密度泛函理论(DFT)计算,以揭示两种对映体对映选择性的潜在机制。
Facile Synthesis of Quinoxaline-2-thiol and Quinoxaline from α-Oxosulfines and o-Arylenediamines
作者:Jun Dong、Xingcai Huang、Youwei Chen
DOI:10.1055/a-1740-5785
日期:2022.6
A series of quinoxaline-2-thiols and quinoxalines were prepared in moderate to good yields from various phenacyl sulfoxides bearing 1-methyl-1H-tetrazole and o-arylenediamines. The proposed reaction mechanism involves generation of sulfines from the phenacyl sulfoxides bearing 1-methyl-1H-tetrazole through thermolysis elimination. Then, site-selective carbophilic addition of sulfines by o-arylenediamines
An easy and efficient copper-catalyzed reaction for the synthesis of quinoxalines from o-phenylenediamines and nitroolefins is developed. This reaction could proceed well without additional base and be applied to various available substrates with a one-step synthetic procedure in moderate to good yields. (c) 2012 Elsevier Ltd. All rights reserved.
α-Nitro Epoxides in Organic Synthesis: Development of a One-Pot Organocatalytic Strategy for the Synthesis of Quinoxalines
作者:Mohammad M. Ibrahim、Dominik Grau、Frank Hampel、Svetlana B. Tsogoeva
DOI:10.1002/ejoc.201301591
日期:2014.3
A new strategy for the synthesis of biologically active quinoxalines by using versatile α-nitroepoxides as starting compounds has been developed. In addition, the in situ organocatalytic epoxidation of electron-poor nitro olefins followed by condensation with 1,2-phenylenediamines to provide quinoxalines in one pot has been demonstrated.
A novel Ir-catalyzed asymmetric hydrogenation protocol for the synthesis of chiral tetrahydroquinoxaline (THQ) derivatives has been developed. By simply adjusting the reaction solvent, bothenantiomers of mono-substituted chiral THQs could be selectively obtained in high yields with excellent enantioselectivities (toluene/dioxane: up to 93% yield and 98% ee (R); EtOH: up to 83% yield and 93% ee (S))
开发了一种用于合成手性四氢喹喔啉 (THQ) 衍生物的新型 Ir 催化不对称氢化方案。通过简单地调整反应溶剂,即可高产率地选择性地获得单取代手性 THQ 的两种对映体,且具有优异的对映选择性(甲苯/二恶烷:收率高达 93%,ee ( R ) 高达 98%;EtOH:收率高达 83%)和 93% ee ( S ))。对于2,3-二取代的手性THQ,获得的顺式氢化产物的收率高达95%,dr为20:1,ee为94%。值得注意的是,该方法也适用于连续流动条件下,产生具有相当收率和对映选择性的克级产品(二恶烷:91% 收率和 93% ee ( R );EtOH:90% 收率和 87% ee ( S ))。与之前报道的 Ir 催化不对称氢化方案不同,该系统表现出显着的改进,因为它不需要额外的添加剂。此外,还进行了全面的机理研究,包括氘标记实验、对照实验、动力学研究和密度泛函理论(DFT)计算,以揭示两种对映体对映选择性的潜在机制。