In this work, six novelaxiallyunfixed biaryl‐based water‐compatible bifunctionalorganocatalysts were designed and synthesized for the organocatalytic access to a variety of 3‐alkyl‐3‐hydroxy‐2‐oxindole derivatives via aldol reactions in water. Organocatalyzed by 5a, the direct aldol reactions of isatins with enolisable ketones underwent readily in water, furnishing the structurally diverse 3‐al
Enantioselectivealdolreactions of various isatins with ketones using newly designed amino amide organocatalysts were found to provide chiral 3-substituted 3-hydroxy-2-oxindoles in good to excellent yields and with excellent stereoselectivities (up to 99 %, up to 98 % ee, syn/anti = 99:1); one catalyst, 3i, proved particularly successful. One of the resulting oxindoles, 3-hydroxy-3-(2-oxocyclohexyl)-2-indolinone
EnantioselectiveAldol Reaction Between Isatins and Cyclohexanone Catalyzed by Amino Acid Sulphonamides
作者:Jun Wang、Qi Liu、Qing Hao、Yanhua Sun、Yiming Luo、Hua Yang
DOI:10.1002/chir.22433
日期:2015.4
Sulphonamides derived from primary α‐aminoacid were successfully applied to catalyze the aldolreaction between isatin and cyclohexanone under neat conditions. More interestingly, molecular sieves, as privileged additives, were found to play a vital role in achieving high enantioselectivity. Consequently, high yields (up to 99%) along with good enantioselectivities (up to 92% ee) and diastereoselectivities
<i>In Situ</i>Formed Bifunctional Primary Amine-Imine Catalyst: Application to the Construction of Chiral Tertiary Alcohols through Asymmetric Aldol-Type Reaction
An in situ formation method to obtain chiral bifunctionalprimary amine‐imine catalysts from the C2‐symmetric chiral diimines has been developed. The efficiency of this method in the construction of chiral tertiary alcohols which are valuable pharmaceutical intermediates is proved by its application to the asymmetricaldol‐type reaction of cyclic ketones with other activated ketone compounds as the
Organocatalyzed direct asymmetric aldol reaction of isatins in water: low catalyst loading in command
作者:Akshay Kumar、Swapandeep Singh Chimni
DOI:10.1016/j.tet.2013.04.044
日期:2013.6
Simple primary tertiary diamines easily derived from natural primary amino acids have been used to catalyze the aldol reactions in water. The 1 mol % of diamine catalyst is sufficient to catalyze the aldol reaction of cyclohexanone/acetone to isatins provided 3-substituted-3-hydroxy-2-oxindole in good yield and good enantioselectivity. The methodology highlights the importance of low catalyst loading in achieving high enantioselectivity. (C) 2013 Elsevier Ltd. All rights reserved.