Enantioselectivity switch controlled by N,N′-di- or N,N,N′,N′-tetra-substituted chiral thiophosphorodiamide ligands, structural relatives of thioureas, in catalytic additions of diethylzinc to aldehydes
摘要:
We have developed a series of new chiral thiophosphorodiamide ligands derived from (1R,2R)-(+)-1,2-diphenylethylenediamine, which are the structural relatives of thioureas. An investigation into their catalytic properties in asymmetric additions of diethylzinc to aldehydes has shown that N,N,N',N'-tetra-substituted chiral thiophosphorodiamides can give (R)-secondary alcohols with up to 98% yield and 98% ee, while N,N'-di-substituted chiral thiophosphorodiamides give (S)-secondary alcohols with up to 99% yield and 97% ee values. The enantioselectivity switch is highly efficient with a broad substrate scope. We have also proposed hypothetical reaction pathways, which result in an enantioselectivity switch. (C) 2013 Elsevier Ltd. All rights reserved.
作者:Wen-Ting Meng、Yan Zheng、Jing Nie、Heng-Ying Xiong、Jun-An Ma
DOI:10.1021/jo302419e
日期:2013.1.18
A facile one-pot sequential conjugate addition/dearomative fluorination transformation of isoxazol-5(4H)-ones with nitroolefins and N-fluorobenzenesulfonimide (NFSI) has been developed. By using a bifunctional chiral tertiary amino-thiourea catalyst, a series of chiral fluorinated isoxazol-5(4H)-ones containing one fluorine-substituted quarternary stereocenter were obtained in high yields with high
Chiral Sensor for Enantiodiscrimination of Varied Acids
作者:Huayin Huang、Guangling Bian、Hua Zong、Yabai Wang、Shiwei Yang、Huifeng Yue、Ling Song、Hongjun Fan
DOI:10.1021/acs.orglett.6b00088
日期:2016.6.3
A chiral thiophosphoroamide 4 derived from (1R,2R)-1,2-diaminocyclohexane is used as a highly effective chiralsensor for the chiral recognition of varied acids via ion-pairing and hydrogen-bonding interactions using 1H, 19F and 31P NMR.
衍生自(1 R,2 R)-1,2-二氨基环己烷的手性硫代磷酰胺4用作高效的手性传感器,通过使用1 H,19 F和19 H的离子对和氢键相互作用手性识别各种酸31 P NMR。
Multifunctional Catalysts in the Asymmetric Mannich Reaction of Malononitrile with <i>N</i>-Phosphinoylimines: Coactivation by Halogen Bonding versus Hydrogen Bonding
enantioselective Mannich reaction between malononitrile and diphenylphosphinoyl-protected aldimine affording products in high yields (up to 98%) and moderate to high enantiomeric purities (ee up to 89%). Typically, noncovalent catalysts rely on several weak interactions to activate the substrate, with one or two of these giving the most notable contribution to activation. In this instance, instead of the