93098-67-0Relevant articles and documents
Co-Polymeric Nanosponges from Cellulose Biomass as Heterogeneous Catalysts for amine-catalyzed Organic Reactions
Riva, Laura,Punta, Carlo,Sacchetti, Alessandro
, p. 6214 - 6222 (2020/10/02)
Heterogeneous catalysts prepared from biomass waste sources are attracting increasing interest. The reasons rely on the possibility of combining the virtuous approach of circular economy with the consolidated advantages of heterogeneous catalysis, namely the recycling of the system and the possibility to drive selectivity towards desired products. Herein we report a highly porous cellulose-based nanosponge (CNS) and its use as a recoverable catalyst for Henry and Knoevenagel reactions, two classical amino-catalyzed transformations. The material is obtained by cross-linking between TEMPO-oxidized cellulose nanofibers (TOCNF) and branched polyethyleneimine 25 kDa (bPEI) in the presence of citric acid. CNS have been developed as sorbent materials for water remediation but their use as heterogeneous catalysts was never investigated. The fully characterized micro- and nano-porous system guarantees a complete penetration of CNS, allowing reagents to diffuse within. Indeed, by modulating reaction conditions (catalyst loading, temperature, solvent, microwave versus conventional heating, relative ratio of reagents) it was possible to drive selectivity towards the desired products, while maintaining high efficiency in terms of conversion. The catalyst could be re-used several times without losing in catalytic efficiency. In most cases the products’ distribution is quite different from homogeneous conditions, this much more emphasizing the importance of this heterogeneous solution.
Copper-catalysed domino reaction of 2-bromobenzylidenemalonates and 1,3-dicarbonyls for the synthesis of chromenes
Saebang, Yotsakorn,Rukachaisirikul, Vatcharin,Kaeobamrung, Juthanat
supporting information, p. 168 - 171 (2016/12/26)
4H-Chromenes were synthesized from 2-bromobenzylidenemalonates and 1,3-dicarbonyls under mild and simple reaction conditions via copper-catalysed domino reactions involving Michael addition and intramolecular Ullmann-type C(aryl)–O bond formation. Althoug
Asymmetric michael addition of N-tert-butanesulfinyl imidate with α,β-unsaturated diesters: Scope and application to the synthesis of indanone derivatives
Wang, Jinfang,Zhou, Yu,Zhang, Lei,Li, Zeng,Chen, Xianjie,Liu, Hong
supporting information, p. 1508 - 1511 (2013/06/27)
An additive-free and highly diastereoselective Michael addition reaction of an N-tert-butanesulfinyl imidate to α,β-unsaturated diesters has been developed using LDA as a base with good to excellent yields. The utility of this chemistry is further demonstrated by the asymmetric synthesis of 3-substituted indanone derivatives 8a, 8d, 8e, and 8i with high enantiomeric excess, which are potential building blocks for preparing biologically active lead compounds.