β-二羰基化合物对硝基烯烃的对映选择性迈克尔加成是通过使用固定化的 N 端胍基肽 H 2 NC (=NH)-Trp-Trp-(Leu-Leu-Aib) 3 -PEG-PS 实现的-树脂(Aib=2-氨基异丁酸),作为催化剂。可行的亲核试剂是乙酰丙酮、丙二酸二甲酯和β-酮酯。亲电子试剂包括苯环上带有各种取代基的β-硝基苯乙烯和脂肪族硝基烯烃。空间拥挤的α-乙氧羰基-β-硝基苯乙烯也成功反应。树脂负载催化剂可循环使用5次。
Novel chiral hydrogen bond donor catalysts based on a 4,5-diaminoxanthene scaffold: application to enantioselective conjugate addition of 1,3-dicarbonyl compounds to nitroalkenes
Novelchiral hydrogen bond donor catalysts based on a 4,5-diamino-9,9′-dimethylxanthene skeleton were designed and synthesized. Among the phenylurea-amide hybrid molecules prepared from various natural/unnatural chiral amino acids, the phenylalanine-derived catalyst, and the proline-derived catalyst were successfully applied to enantioselective conjugate addition of 1,3-dicarbonyl compounds to nitroalkenes
Design and synthesis of cinchona-based chiral hyperbranched polymers and their application in asymmetric reactions
作者:Sadia Afrin Chhanda、Shinichi Itsuno
DOI:10.1016/j.tet.2020.131247
日期:2020.6
(MH) coupling reaction. AB2 and A2B-type chiral monomers were prepared from cinchona squaramide derivatives, where A (vinyl) reacted only with B (iodophenyl) under MH reactionconditions. The chiral HBPs obtained by the MH polymerization contained cinchona squaramide moieties and demonstrated excellent diastereoselectivity and enantioselectivity in asymmetricMichael addition reactions of methyl 2-
[EN] ASYMMETRIC MICHAEL AND ALDOL ADDITION USING BIFUNCTIONAL CINCHONA-ALKALOID-BASED CATALYSTS<br/>[FR] ADDITIONS ASYMETRIQUES DE MICHAEL ET D'ALDOL UTILISANT DES CATALYSEURS BIFONCTIONNELS A BASE DE CINCHONINE
申请人:UNIV BRANDEIS
公开号:WO2005121137A1
公开(公告)日:2005-12-22
One aspect of the present invention relates to quinine-based and quinidine-based catalysts. Another aspect of the invention relates to a method of preparing a derivatized quinine-based or quinidine-based catalyst comprising 1) reacting quinine or quinidine with 5 base and a compound that has a suitable leaving group, and 2) converting the ring methoxy group to a hydroxy group. Another aspect of the present invention relates to a method of preparing a chiral, non-racemic compound from a prochiral electron-deficient alkene or azo compound or prochiral aldehyde or prochiral ketone, comprising the step of: reacting a prochiral electron-deficient alkene or azo compound or prochiral aldehyde or prochiral 10 ketone with a nucleophile in the presence of a catalyst; thereby producing a chiral, non racemic compound; wherein said catalyst is a derivatized quinine or quinidine. Another aspect of the present invention relates to a method of kinetic resolution, comprising the step of reacting racemic chiral alkene with a nucleophile in the presence of a derivatized quinine or quinidine.
Ephedrine- and Pseudoephedrine-Derived Thioureas in Asymmetric Michael Additions of Keto Esters and Diketones to Nitroalkenes
作者:Carsten Bolm、Angelika Flock、Anke Krebs
DOI:10.1055/s-0029-1219582
日期:2010.5
Ephedrine-derived bifunctional thioureas have been synthesized and applied as organocatalysts in Michael additions of 1,3-dicarbonyl compounds to nitroalkenes.
Synthesis of cinchona squaramide polymers by Yamamoto coupling polymerization and their application in asymmetric Michael reaction
作者:Sadia Afrin Chhanda、Shinichi Itsuno
DOI:10.1016/j.reactfunctpolym.2021.104913
日期:2021.7
chiral polymers were successfully utilized as polymeric catalysts in asymmetricMichael addition reactions. Good to excellent enantioselectivities were observed for different types of asymmetricMichaelreactions. Using the chiral homopolymer catalyst P4, almost perfect diastereoselectivity (>100:1) with 99% ee was obtained for the reaction between methyl 2-oxocyclopentanecarboxylate 25 and trans-β-nitrostyrene