the isatin-acetone reaction at higher temperatures without compromising enantioselectivity is reported. Kamlet-Taftbasicity (β) and proticity (α) of solvents were found to be crucial in describing the solubility of isatin and performance of L-leucinol organocatalyst and informed the choice of solvent for transfer to flow.
trans-4-Hydroxy-l-prolinamide as an efficient catalyst for direct asymmetric aldol reaction of acetone with isatins
作者:Geeta Devi Yadav、Surendra Singh
DOI:10.1016/j.tetasy.2016.04.008
日期:2016.7
Prolinamide (2S,4R)-4-hydroxy-N-((S)-1-phenylethyl)pyrrolidine-2-carboxamide was found to be an efficient organocatalyst (10 mol %) for the direct asymmetric aldol reactions of isatins with acetone at -35 degrees C in THF and afforded the product in 79% yield with 74% ee. We have generalised the methodology for the direct asymmetric aldol reaction between isatin derivatives and acetone, and the corresponding aldol products were obtained in high yields (up to 99%) and with moderate enantioselectivities (up to 80%). This method has been applied to the enantioselective synthesis of (S)-convolutamydine. (C) 2016 Elsevier Ltd. All rights reserved.
Enantioselective Aldol Reaction between Isatins and Ketones, Catalyzed by Chiral Norephedrine-Derived β-Amino Alcohols with a Thiophene Moiety
作者:A. E. Aydin
DOI:10.1134/s1070428022060100
日期:2022.6
Cu(<scp>ii</scp>)-thiophene-2,5-bis(amino-alcohol) mediated asymmetric Aldol reaction and Domino Knoevenagel Michael cyclization: a new highly efficient Lewis acid catalyst
作者:Abdullah Mohammed Al-Majid、Abdullah Saleh Alammari、Saeed Alshahrani、Matti Haukka、Mohammad Shahidul Islam、Assem Barakat
DOI:10.1039/d2ra00674j
日期:——
acid-catalytic system Cu(II)-thiophene-2,5-bis(amino-alcohol) has been developed for enantioselective Aldol reaction of isatin derivatives with ketones. The new catalytic system also proved to be highly enantioselective for the one pot three-component Domino Knoevenagel Michael cyclization reaction of substituted isatin with malononitrile and ethylacetoacetate. The chiral ligand (2S,2′S)-2,2′-((thiophene-2
高效路易斯酸催化体系Cu( II )-噻吩-2,5-双(氨基-醇)已被开发用于靛红衍生物与酮的对映选择性羟醛反应。新的催化体系还被证明对取代靛红与丙二腈和乙酰乙酸乙酯的一锅三组分Domino Knoevenagel Michael环化反应具有高度对映选择性。手性配体 (2 S ,2' S )-2,2'-((噻吩-2,5-二基双(亚甲基))双(氮杂二基))双(3-苯基丙-1-醇) ( L1 ) 组合使用 Cu(OAc) 2 ·H 2 O 作为新型路易斯酸催化剂,以良好至优异的产率 (81–99%) 和高对映选择性制备了 3-取代-3-羟基二氢吲哚-2-酮衍生物 ( 3a–s ) (高达 96% ee)和螺[4 H -吡喃-3,3-羟吲哚]衍生物( 6a–l )具有优异的产率(89–99%)和高 ee(高达 95%)。这些羟醛产物和螺羟吲哚构成了大量药物活性分子和天然产物的核心结构基序。