B(C6F5)3-Catalyzed tandem cyclization/hydrosilylation for the step-economical construction of 1,2,3,4-tetrahydroquinoxalines from readily available starting materials has been developed.
B(C6F5)3催化的串联环化/氢硅烷化反应,可从易得的起始物构建1,2,3,4-四氢喹啉。
PROCESS FOR PRODUCING OPTICALLY ACTIVE AMINE
申请人:TAKASAGO INTERNATIONAL CORPORATION
公开号:US20150210657A1
公开(公告)日:2015-07-30
A process for producing an optically active amine compound, characterized by asymmetrically hydrogenating a prochiral carbon-nitrogen double bond in the presence of a ruthenium complex represented by general formula (1) or (2) (wherein P
represents an optically active diphosphine, X represents an anionic group, and Ar represents an optionally substituted arylene group).
An investigation employing the catalytic system consisting of (pentamethylcyclopentadienyl)rhodium dichloride dimer [Cp*RhCl2]2 and 2,2′-bipyridine (bpy) for transferhydrogenation of a variety of quinoxalines, quinoxalinones, quinolines and indoles under aqueous conditions with formate as the hydrogen source is reported. This approach provides various tetrahydroquinoxalines, dihydroquinoxalinones
Rhodium-catalyzed transfer hydrogenation of quinoxalines with water as a hydrogen source
作者:Xia Zhang、Jingchao Chen、Ruhima Khan、Guoli Shen、Zhenxiu He、Yongyun Zhou、Baomin Fan
DOI:10.1039/c9ob02095k
日期:——
Rhodium-catalyzed transfer hydrogenation of quinoxalines with water as a hydrogensource was reported. The reaction allowed the simple preparation of tetrahydroquinoxalines under mild conditions. The deuterium-labelling experiment confirmed that water is the sole hydrogensource in the transfer hydrogenation reaction.
The combination of [Cp*IrCl2](2) with N-(2-aminoethyl)-4-(trifluoromethyl)benzenesulfonamide constitutes an efficient catalyst for selective transfer hydrogenation of a variety of quinoxalines in water with HCOONa as the hydrogen source, affording the corresponding tetrahydroquinoxalines in good to excellent yields. The catalyst is air-stable, and the reduction could be performed without nitrogen protection. The aqueous phase reduction is shown to be highly pH-dependent, with acidic pH leading to better results. There exits a pH window for optimum rate, and the use of HOAc/NaOAc buffer solution is essential for maintaining a stable pH during the reaction. (C) 2011 Elsevier Ltd. All rights reserved.