An Efficient Method for Cleavage of Epoxides with Aromatic Amines

Regioselective ring opening of 2,2-dicyanooxiranes by 1,3-dinucleophiles in the presence of Lewis acids such as bismuth(III) nitrate pentahydrate [Bi(NO3)3·5H2O] and zirconium(IV) chloride (ZrCl4)

“…Direct reuse of the catalysts (Table 4, entry 2, 6) led to a greater than 15 % decrease in activity, while washing with dichloromethane and ethylacetate prior to reuse also resulted in lower conversions (Table 4, entry 3,4,7,8). This phenomenon probably arose because the reactant and product were not completely desorbed from the catalyst, and therefore the active sites were blocked.…”

“…The requirement for high temperature in epoxides sensitive to this condition led to the necessity for activation of the epoxide rings to increase their susceptibility to nucleophilic attack. The various methodologies developed for this purpose include the use of Lewis acid catalysts such as alumina [7], metal triflates [8], transition-metal halides [9], alkalimetal perchlorates [10], silica under high pressure [11], and montmorillonite clay under microwave irradiation [12]. The search for new and efficient Lewis acid catalysts for various useful organic transformations is one of the most important, interesting, and challenging research topics in catalytic synthesis.…”

Synthesis and modification of epoxy‐ and hydroxy‐functional microspheres

“…21,22 However, if the amine or the epoxide is sterically hindered, addition can be slow even at elevated temperatures, and Lewis acids are required to catalyze the reaction. 23,24 This is the case with the epoxycyclo-hexane groups bound to the surface of the microspheres. To examine the efficiency of this reaction, a sample of microspheres (II) was refluxed with benzylamine in the presence of a trace of boron trifluoride-tetrahydrofuran complex.…”

Three‐Membered Heterocycles. Structure and Reactivity

“…The addition of aromatic amines can be catalyzed by stannic or cupric triflate [556,557]; b-cyclodextrin [558]; zirconium(IV) chloride [559] or bismuth trichloride [560,561] in acetonitrile; and zinc oxide [562], ytterbium(III) nitrate [563], or a mesoporous silica immobilized cobalt complex [564] under solvent-free conditions. A ruthenium catalyst in the presence of tin chloride also results in an S N 1-type substitution behavior with aniline derivatives (e.g., 522), but further provides for subsequent cyclization of the intermediate amino alcohol, thus representing an interesting synthesis of 2-substituted indoles (e.g., 523) [565].…”