Design and synthesis of novel natural clinoptilolite-MnFe2O4 nanocomposites and their catalytic application in the facile and efficient synthesis of chalcone derivatives through Claisen-Schmidt reaction
the aldol-type Claisen–Schmidt reaction for the synthesis of chalcones. A strong catalytic synergy was observed between nano-MnFe2O4 particles and natural clinoptilolite in the structure of these nanocomposites. The products with a broad range of substituents on the reactants were efficiently obtained under room-temperature conditions within relatively short reaction times with good to excellent yields
通过使用各种量的锰铁氧体(MnFe 2 O 4)纳米粒子修饰天然斜发沸石的表面,制备了一系列三种新型纳米复合材料。通过XRD,FT-IR,EDX,VSM和TEM分析,可以充分表征这些锰铁氧体改性的纳米复合材料(MFO-NC)。在斜发沸石(MFO–NC-3)中含有40 wt%锰铁氧体的这些新型纳米复合材料之一在醛醇型Claisen–Schmidt反应中显示了强大的催化行为,可合成查耳酮。在纳米MnFe 2 O 4之间观察到强烈的催化协同作用这些纳米复合材料的结构中存在颗粒和天然斜发沸石。在一种制备的MFO-NC纳米复合材料的存在下,在室温条件下,在较短的反应时间内即可有效地获得在反应物上具有广泛取代基的产物,并具有良好或优异的收率。这种纳米复合材料在查耳酮的合成中也显示出很强的稳定性和可重复使用性。
CBr<sub>4</sub> as a Halogen Bond Donor Catalyst for the Selective Activation of Benzaldehydes to Synthesize α,β-Unsaturated Ketones
作者:Imran Kazi、Somraj Guha、Govindasamy Sekar
DOI:10.1021/acs.orglett.7b00348
日期:2017.3.3
CBr4 has been employed as a halogen bond donor catalyst for the selective activation of aldehyde, to achieve an efficient solvent- and metal-free C═C bond forming reaction in the presence of strong acid sensitive groups such as methoxy, cyanide, ester, and ketal for the synthesis of α,β-unsaturated ketones. This unique capability of CBr4 to act as a halogen bond donor has been explored and established
作者:Roland U. Braun、Markus Ansorge、Thomas J. J. Müller
DOI:10.1002/chem.200600530
日期:2006.12.4
coupling of electron-deficient (hetero)aryl halides 1 and (hetero)aryl or alkenyl 1-propargyl alcohols 2 does not terminate at the stage of the expected internal propargyl alcohols, but rather gives rise to the formation of alpha,beta-unsaturated ketones 3 with a variety of acceptor substituents. This new domino reaction, a coupling-isomerization reaction (CIR), can be rationalized as a sequence of