Catalytic Asymmetric Protonation of Silyl Ketene Imines
摘要:
An efficient catalytic and highly enantioselective protonation of silyl ketene imines is described. The reaction is catalyzed by the chiral phosphoric acids TRIP or STRIP in the presence of a stoichiometric amount of methanol as the proton source and silyl acceptor. A variety of substituted racemic silyl ketene imines have been transformed into highly enantioenriched nitriles.
A cyanide‐free platform technology for the synthesis of chiral nitriles by biocatalytic enantioselective dehydration of a wide range of aldoximes is reported. The nitriles were obtained with high enantiomeric excess of >90 % ee (and up to 99 % ee) in many cases, and a “privileged substrate structure” with respect to high enantioselectivity was identified. Furthermore, a surprising phenomenon was observed
Enantioselective Synthesis of (<i>R</i>)-2-Arylpropanenitriles Catalysed by Ene-Reductases in Aqueous Media and in Biphasic Ionic Liquid-Water Systems
作者:Elisabetta Brenna、Michele Crotti、Francesco G. Gatti、Alessia Manfredi、Daniela Monti、Fabio Parmeggiani、Sara Santangelo、Davila Zampieri
DOI:10.1002/cctc.201402205
日期:2014.8
The enantioselective reduction of α‐methylene nitrile derivatives catalysed by ene‐reductases affords the corresponding (R)‐2‐arylpropanenitriles with high conversion values. The reaction is investigated either in aqueous medium (with an organic cosolvent or by loading the substrate onto hydrophobic resins) or in a biphasicionicliquid–watersystem. The use of ionic liquids, herein with isolated ene‐reductases
Cu-catalyzed enantioselective decarboxylative cyanation <i>via</i> the synergistic merger of photocatalysis and electrochemistry
作者:Yin Yuan、Junfeng Yang、Junliang Zhang
DOI:10.1039/d2sc05428k
日期:——
The development of an efficient and straightforward method for decarboxylative coupling using common alkyl carboxylic acid is of great value. However, decarboxylative coupling with nucleophiles always needs stoichiometric chemical oxidants or substrate prefunctionalization. Herein, we report a protocol for Cu-catalyzed enantioselectivedecarboxylative cyanation via the merger of photocatalysis and