38323-04-5Relevant articles and documents
Organocatalytic Knoevenagel condensation by chiral: C 2-symmetric tertiary diamines
Gu, Xiaoyu,Tang, Yan,Zhang, Xiang,Luo, Zinbin,Lu, Hongfei
supporting information, p. 6580 - 6583 (2016/08/09)
The efficient Knoevenagel condensation catalyzed by (1S,2S)-1,2-diaminocyclohexane derivatives is presented and investigated. Various aliphatic aldehydes undergo condensation with active methylene compounds to yield the corresponding products in high yields. α-Branched aldehydes were found to be efficiently converted to the corresponding enantiomerically enriched products by using these chiral tertiary diamine catalysts.
Indium(III)-catalyzed knoevenagel condensation of aldehydes and activated methylenes using acetic anhydride as a promoter
Ogiwara, Yohei,Takahashi, Keita,Kitazawa, Takefumi,Sakai, Norio
, p. 3101 - 3110 (2015/03/30)
The combination of a catalytic amount of InCl3 and acetic anhydride remarkably promotes the Knoevenagel condensation of a variety of aldehydes and activated methylene compounds. This catalytic system accommodates aromatic aldehydes containing a variety of electron-donating and -withdrawing groups, heteroaromatic aldehydes, conjugate aldehydes, and aliphatic aldehydes. Central to successfully driving the condensation series is the formation of a geminal diacetate intermediate, which was generated in situ from an aldehyde and an acid anhydride with the assistance of an indium catalyst.
The catalytic asymmetric Knoevenagel condensation
Lee, Anna,Michrowska, Anna,Sulzer-Mosse, Sarah,List, Benjamin
experimental part, p. 1707 - 1710 (2011/04/22)
116 years after the discovery of the Knoevenagel condensation, the first catalytic asymmetric variant has been developed. Dynamic kinetic resolution in the reaction of α-branched aldehydes with malonates in the presence of a newly designed and readily available modified cinchona amine catalyst gives the corresponding alkylidene malonates in high enantioselectivity (see scheme).
Asymmetric Induction in Carbonyl Analogues: Comments on Models
Kruger, Diana,Sopchik, Alan E.,Kingsbury, C.A.
, p. 778 - 788 (2007/10/02)
Organometallic reagent additions to certain carbonyl analogues are reported.The compounds in question have C=C(CN)2 or C=C(CO2R)2 in place of CO.The ground-state conformation of these analogues is quite specific.Some of the additions obey the Cram et al. rules for asymmetric induction but require that approach of the organometallic reagent occurs over the L group in the ground-state conformation.This is taken as an indication that the ground-state conformation is not relevant, in agreement with the Curtin-Hammett principle.In other cases, little asymmetric induction is observed.A third type of behavior concerns opposite modes of addition to the dicyanide vs. the diester substrates.The variability of the data are discussed in terms of the validity of rules for asymmetric induction.Secondary isotope effects are explored in an attempt to resolve the dichotomy between additions to cyclic vs. acyclic ketones.The suggestion is made that the dichotomy in stereochemistry of addition may be related to a kinetically significant conformational change in cyclohexanones vs. acyclic substrates or cyclopentanones.
