نتایج جستجو برای: ring opening of epoxides
تعداد نتایج: 21178628 فیلتر نتایج به سال:
The minute amount of hydrogen sulfate groups introduced into the graphene oxide (GO) obtained by Hummers oxidation of graphite renders this material as a highly efficient, recyclable acid catalyst for the ring opening of epoxides with methanol and other primary alcohols as nucleophile and solvent.
We report the alternating ring-opening copolymerization of dihydrocoumarin with epoxides catalyzed by chromium(III) salen complexes. This process provides access to a range of perfectly alternating polyesters with high molecular weights and narrow molecular weight distributions. Atactic poly(cyclohexene dihydrocoumarate) and poly(cyclopentene dihydrocoumarate) were found to be semi-crystalline ...
A unifying stereochemical analysis for the formation of the constitutional isomeric halogenated C(15)-acetogenin medium-ring ether natural products from Laurencia species is presented, where an intramolecular bromonium ion assisted epoxide ring-opening reaction of enantiomerically pure epoxides can account for ring-size, the position of the halogen substituents, and relative and absolute config...
•Unprecedented zirconocene catalysis in reductive ring opening of epoxides•Broad reactivity across diverse substrates, including natural products•Reverse regioselectivity compared with the well-established methods titanocene•Changing metal center metallocene alters reversibility Epoxides are key structural motifs commonly found products and medicinal agrochemical agents as well various intermed...
The present study, for the first time, presents a feasible protocol for the preparation of β-cyclodextrin/ imidazolium based dicationic ionic liquid, [βCD/Im](OTs)2, and its application as an efficient and eco-friendly microvessel and host ionic liquid system for the regioselective ring opening of the epoxides in water. No evidence for the formation of diol by-products or side reacti...
In this study, Cu-Ni-Fe-Cr layered double hydroxide (LDH) immobilized on silica magnetite (Fe3O4@SiO2@Cu-Ni-Fe-Cr LDH) was investigated towards ring opening of diverse epoxides with acetic anhydride to afford vic-diacetates within 15–40 min in high yields. Reusability the nano-LDH also studied for 6 consecutive cycles without significant loss catalytic activity.
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