72709-61-6Relevant articles and documents
Supramolecular autoregulation
Rodríguez-Llansola, Francisco,Meijer
, p. 6549 - 6553 (2013)
Enzyme activity in biological systems is often governed by control mechanisms in which the catalytic properties are made sensitive or insensitive to differences in enzyme or substrate concentration. Here, we report the first supramolecular system where th
Computational Investigations of Enantioselection in Carbon-Carbon Bond Forming Reactions of Ruthenium Guanidinobenzimidazole Second Coordination Sphere Hydrogen Bond Donor Catalysts
Wititsuwannakul, Taveechai,Mukherjee, Tathagata,Hall, Michael B.,Gladysz, John A.
, p. 1149 - 1162 (2020)
The NH2 group of 2-guanidinobenzimidazole (GBI) can be replaced by (RCRC)-NHCH(CH2)4CHNMe2 and elaborated to the enantiopure chelate salts (SRuRCRC)-[(η5-C5H5)Ru(CO)(GBICH(CH2)4CHNMe2)]+PF6- ((SRuRCRC)-2+PF6-) and (RRuRCRC)-2+PF6-. These catalyze highly e
Synthesis, characterization and catalytic performance in enantioselective reactions by mesoporous silica materials functionalized with chiral thiourea-amine ligand
G?k, Ya?ar,G?k, Halil Zeki
, p. 853 - 874 (2020/11/10)
Chiral heterogeneous catalysts have been synthesized by grafting of silyl derivatives of (1R, 2R)- or (1S, 2S)-1,2-diphenylethane-1,2-diamine on SBA-15 mesoporous support. The mesoporous material SBA-15 and so-prepared chiral heterogeneous catalysts were characterized by a combination of different techniques such as X-ray diffractometry (XRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) surface area. Results showed that (1R, 2R)- and (1S, 2S)-1,2-diphenylethane-1,2-diamine were successively immobilized on SBA-15 mesoporous support. Chiral heterogeneous catalysts and their homogenous counterparts were tested in enantioselective transfer hydrogenation of aromatic ketones and enantioselective Michael addition of acetylacetone to β-nitroolefin derivatives. The catalysts demonstrated notably high catalytic conversions (up to 99%) with moderate enantiomeric excess (up to 30% ee) for the heterogeneous enantioselective transfer hydrogenation. The catalytic performances for enantioselective Michael reaction showed excellent activities (up to 99%) with poor enantioselectivities. Particularly, the chiral heterogeneous catalysts could be readily recycled for Michael reaction and reused in three consecutive catalytic experiments with no loss of catalytic efficacies.
Molecular Engineering of β-Substituted Oxoporphyrinogens for Hydrogen-Bond Donor Catalysis
Chahal, Mandeep K.,Payne, Daniel T.,Matsushita, Yoshitaka,Labuta, Jan,Ariga, Katsuhiko,Hill, Jonathan P.
supporting information, p. 82 - 90 (2020/01/02)
A new class of bifunctional hydrogen-bond donor organocatalyst using oxoporphyrinogens having increased intramolecular hydrogen-bond donor distances is reported. Oxoporphyrinogens are highly non-planar rigid macrocycles containing a multiple hydrogen bond-forming binding site. In this work, we describe the first example of non-planar OxPs as hydrogen-bond donor catalysts prepared using a molecular engineering approach of the binding site for dual activation of substrates. The introduction of β-substituents is key to the catalytic activity and the catalysts are able to catalyze 1,4-conjugate additions and sulfa-Michael additions, as well as, Henry and aza-Henry reactions at low catalyst loadings (≤ 1 mol-%) under mild conditions. Preliminary mechanistic studies have been carried out and a possible reaction mechanism has been proposed based on the bi-functional activation of both substrates through hydrogen-bonding interactions.
