Enantioselective Henry reaction catalyzed by copper(II)—Cinchona alkaloid complexes
作者:Mariola Zielińska-Błajet、Jacek Skarżewski
DOI:10.1016/j.tetasy.2011.02.003
日期:2011.2
An enantioselective Henry reaction was efficiently carried out under mild reaction conditions in the presence of catalytic 9-epi and natural Cinchonaalkaloids and copper (II) acetate. The best catalytic performance was observed for native quinine (12 mol %) and Cu(OAc)2 (10 mol %). Aromatic and aliphatic aldehydes with nitromethane and its α-substituted derivatives provided the corresponding β-nitroalcohols
Novel bifunctional catalysts having guanidine and thiourea functional groups were developed for the asymmetric Henry (nitroaldol) reaction. Various structural developments of the catalyst revealed that the compound having an octadecyl-substituted guanidine and thiourea groups linked with a chiral spacer derived from phenylalanine, i.e., 1e, efficiently promoted the Henry reaction. This bifunctional
5′-(alkane-2,2-diyl)bis(1H-pyrrole-2-carbaldehydes). These macrocycles, differing for the alkyl/aryl meso-substituents, were used as ligands in the copper-catalyzed Henry reactions of aromatic and aliphatic aldehydes with nitroalkanes. In the optimized experimental conditions, the condensations of nitromethane and aromatic and aliphatic aldehydes in the presence of catalytic amounts of copper diacetate and
Henry reaction of various aldehydes with nitromethane. It was found that these compounds were effective catalysts for this reaction, with enantiomeric excesses being as high as 97%. The enantioselectivities of individual derivatives were different and depended on the substituents attached to stereogenic centers and the configuration of imidazolidine-4-one cycle. High enantiomeric excesses were obtained
catalytic asymmetric Henry reaction has been developed with use of a sulfonyldiamine−CuCl complex as a catalyst. A series of new binaphthyl-containing sulfonyldiamine ligands (2a−h) were readily synthesized in two steps starting from commercially available chiral 1,2-diamines. The (R,R)-diamine-(R)-binaphthyl ligand (2d)−CuCl complex smoothly catalyzed the enantioselective Henry reaction with the assistance