Enantioselective Decarboxylative Cyanation Employing Cooperative Photoredox Catalysis and Copper Catalysis
作者:Dinghai Wang、Na Zhu、Pinhong Chen、Zhenyang Lin、Guosheng Liu
DOI:10.1021/jacs.7b09802
日期:2017.11.8
The merger of photoredoxcatalysis with asymmetric copper catalysis have been realized to convert achiral carboxylic acids into enantiomerically enriched alkyl nitriles. Under mild reaction conditions, the reaction exhibits broad substrate scope, high yields and high enantioselectivities. Furthermore, the reaction can be scaled up to synthesize key chiral intermediates to bioactive compounds.
Ligand Electronic Effects in Asymmetric Catalysis: Enhanced Enantioselectivity in the Asymmetric Hydrocyanation of Vinylarenes
作者:Albert L. Casalnuovo、T. V. RajanBabu、Timothy A. Ayers、Timothy H. Warren
DOI:10.1021/ja00101a007
日期:1994.11
nickel-catalyzed, asymmetric hydrocyanation of vinylarenes using glucose- derived, chiral phosphinite ligands, L, increases dramatically when the ligands contain electron-withdrawing P-aryl substituents. The substrate and solvent also strongly influence the enantioselectivity, with the highest ee's (85-91% for 6-methoxy-2-vinylnaphthalene (MVN)) obtained for the hydrocyanation of electron-rich vinylarenes in a
in this area, it remains challenging to develop enantioselective transformations direct from carboxylic acids. Herein we disclose a photoelectrocatalytic method for the direct and enantioselective decarboxylative cyanation. The photoelectrochemical reactions convert carboxylic acids to enantioenriched nitriles by employing cerium/copper relay catalysis with a cerium salt for catalytic decarboxylation
directly decarboxylative cyanation reactions of common alkyl carboxylic acids remain largely elusive. Herein, we report a protocol for copper-catalyzed direct and enantioselective decarboxylative cyanation of benzylic acids. The in situ activation of acid substrates by a commercially inexpensive hypervalentiodine(III) reagent promoted the yield of the alkyl radicals undermild reaction conditions without
Stereoselective hydrolysis of nitriles and amides under mild conditions using a whole cell catalyst
作者:Timothy Beard、Mark A. Cohen、Julian S. Parratt、Nicholas J. Turner、John Crosby、Jock Moilliet
DOI:10.1016/s0957-4166(00)80215-3
日期:1993.6
An immobilised whole cell Rhodococcus sp. (SP 361) has been shown to be an effective catalyst for the stereoselective hydrolysis of both racemic and prochiral nitrile containing compounds. 2-Alkyl-arylacetonitriles 6a-8a were hydrolysed to (S)-acids and (R)-amides whereas the closely related substrate 9a gave the (R)-acid. A series of prochiral dinitriles 10a-13a were hydrolysed to the corresponding (S)-acids with e.e.'s 22-84%. Models to account for the stereoselectivity of the enzymic hydrolyses have been proposed.