Optimizing the Structure of 4-Dialkylamino-α,α-diarylprolinol Ethers as Catalysts for the Enantioselective Cyclopropanation of α,β-Unsaturated Aldehydes in Water
作者:Jose I. Martínez、Efraim Reyes、Uxue Uria、Luisa Carrillo、Jose L. Vicario
DOI:10.1002/cctc.201300097
日期:2013.8
water as the reaction solvent. Moreover, the reaction was studied by computational methods, which indicated that the overall transformation proceeded through a cascadeMichael/α‐alkylation sequence, in which the first iminium‐mediated Michaeladdition reaction was the rate‐determining step and also the step at which stereochemical information was transferred from the catalyst to the products.
Modular Access to Chiral 2,3-Dihydrofurans and 3,4-Dihydro-2<i>H</i>-pyrans by Stereospecific Activation of Formylcyclopropanes through Combination of Organocatalytic Reductive Coupling and Lewis-Acid-Catalyzed Annulative Ring-Opening Reactions
作者:Swamy Peraka、Akram Hussain、Dhevalapally B. Ramachary
DOI:10.1021/acs.joc.8b01315
日期:2018.9.7
materials, chiral formylcyclopropanes, cyclic-1,3-diones, or CH acids and Hantzsch ester through an organocatalytic reductive coupling reaction at ambient conditions, especially without harming the cyclopropane ring. Chiral cyclopropanes containing cyclic-1,3-diones were stereospecifically transformed into dihydropyrans and dihydrofurans found in many bioactive natural products and drugs through an annulative
开发了有机催化还原偶联和路易斯酸催化的环状开环策略,该方法是两步协议,用于立体选择性地合成二氢吡喃,这是由手性甲酰基环丙烷,CH酸和汉茨sch酯的主要产物。它是一种有效的催化两步方案,用于手性合成二氢吡喃和二氢呋喃。从容易获得的起始原料,手性甲酰基环丙烷,环1,3-二酮或CH酸和Hantzsch酯通过在环境条件下进行有机催化还原偶联反应,特别是在不损害环丙烷环的情况下。3 ·OEt 2)或碳酸铯(Cs 2 CO 3)催化。通过立体定向的亲密离子对途径解释了环丙烷的高度非对映选择性和区域选择性开环。