Asymmetric Pnictogen-Bonding Catalysis: Transfer Hydrogenation by a Chiral Antimony(V) Cation/Anion Pair
作者:Jian Zhang、Jun Wei、Wei-Yi Ding、Shaoyu Li、Shao-Hua Xiang、Bin Tan
DOI:10.1021/jacs.1c02808
日期:2021.5.5
Pnictogen-bonding catalysisbased on σ-hole interactions has recently attracted the attention of synthetic chemists. As a proof-of-concept for asymmetric pnictogen-bonding catalysis, we report herein an enantioselective transfer hydrogenation of benzoxazines catalyzed by a novel chiral antimony cation/anion pair. The chiral pnictogen catalyst library could be rapidly accessed from triarylstibine with
A metal-free hydrogenation of 3-substituted 2H-1,4-benzoxazines
作者:Simin Wei、Xiangqing Feng、Haifeng Du
DOI:10.1039/c6ob01556e
日期:——
A metal-free hydrogenation of 3-substituted 2H-1,4-benzoxazines has been successfully realized with 2.5 mol% of B(C6F5)3 as a catalyst to furnish a variety of 3,4-dihydro-2H-1,4-benzoxazines in 93–99% yields. Up to 42% ee was also achieved for the asymmetric hydrogenation with the use of a chiral diene and HB(C6F5)2.
以2.5摩尔%的B(C 6 F 5)3为催化剂,成功地实现了3取代2 H -1,4-苯并恶嗪的无金属氢化,以提供各种3,4-二氢-2 H -1,4-苯并恶嗪的产率为93-99%。通过使用手性二烯和HB(C 6 F 5)2进行不对称氢化反应,还可以达到高达42%ee 。
4,5-Dihydropyrrolo[1,2-<i>a</i>]quinoxalines: A Tunable and Regenerable Biomimetic Hydrogen Source
A series of tunable and regenerable biomimetic hydrogen sources, 4,5-dihydropyrrolo[1,2-a]quinoxalines, have been synthesized and applied in biomimetic asymmetric hydrogenation of 3-aryl-2H-benzo[b][1,4]oxazines and 1-alkyl-3-aryl-quinoxalin-2(1H)-ones, providing the chiral amines with up to 92% and 89% ee, respectively.
合成了一系列可调和可再生的仿生氢源4,5-二氢吡咯并[1,2- a ]喹喔啉,并将其用于3-芳基-2 H-苯并[ b ] [1,4]的仿生不对称加氢。恶嗪和1-烷基-3-芳基-喹喔啉-2(1 H)-酮,分别为手性胺提供高达92%和89%的ee。
Iridium-Catalyzed Asymmetric Hydrogenation of 3-Substituted 2H-1,4-Benzoxazines
The highly enantioselective hydrogenation of 3-aryl-2H-1,4-benzoxazines was achieved using the (cyclooctadiene)iridium chloride dimer/(S)-SegPhos/iodine [Ir(COD)Cl]2/(S)-SegPhos/I2} system as catalyst with up to 92% ee. The 3-styryl-2H-1,4-benzoxazine derivatives were also hydrogenated by the iridium catalyst and Pd/C in two consecutive steps whereby 93–95% ee values were obtained.
使用(环辛二烯)铱氯化二聚物/(S)-SegPhos /碘[Ir(COD)Cl] 2 /(S)-SegPhos实现对3-芳基2 H -1,4-苯并恶嗪的高度对映选择性氢化/ I 2 }体系作为催化剂,ee最高可达92%。3-styryl-2 H -1,4-苯并恶嗪衍生物还通过铱催化剂和Pd / C在两个连续的步骤中进行氢化,从而获得93-95%ee值。
[Ir(P−OP)]-Catalyzed Asymmetric Hydrogenation of Diversely Substituted C═N-Containing Heterocycles
作者:José Luis Núñez-Rico、Anton Vidal-Ferran
DOI:10.1021/ol400854a
日期:2013.4.19
Iridium(I) complexes of enantiomerically pure phosphine-phosphite ligands ([Ir(Cl)(cod)(P—OP)]) efficiently catalyze the enantioselectivehydrogenation of diverse C═N-containing heterocyclic compounds (benzoxazines, benzoxazinones, benzothiazinones, and quinoxalinones; 25 examples, up to 99% ee). A substrate-to-catalyst ratio as high as 2000:1 was reached.