نتایج جستجو برای: asymmetric 1-3-dipolar
تعداد نتایج: 3645654 فیلتر نتایج به سال:
Synthesis of enantiomerically pure isoxazolidine via an asymmetric 1,3- dipolar cycloaddition reaction of nitrone with electron-deficient dipolarophile was described. The process occurs at room temperature in aqueous ethanol as a green solvent and in the presence of a bidendate bis(imine)–Cu(II)triflate complex as catalyst. The reaction mechanism is discussed on the basis of the assignment of t...
The catalytic highly regio-, diastereo-, and enantioselective synthesis of a small library of spiropyrrolizidineoxindolesvia a four-component 1,3-dipolar cycloaddition reaction of azomethine ylides, derived from isatin, with electron-deficient dipolarophilewas described. The process occurs at room temperature in aqueous ethanol as a green solvent and in the presence of a bidendatebis(imine)–Cu(...
An asymmetric erbium(III) Schiff base complex [Er(HL)2(NO3)3] was synthesized which shows SMM behaviour with an Ueff of 5.2 K. Dipolar interaction in 1 significantly reduced upon dilution which increases the barrier height to 51.5 K. Ab initio calculations were performed to shed light on the mechanism of magnetization relaxation.
Abstract This review updates the field of enantioselective indium-catalyzed transformations all types since 2012. It shows that asymmetric indium catalysis, suits growing demand for greener processes, offers a real opportunity to replace toxic metals in near future. 1 Introduction 2 Allylations, Propargylations, and Allenylations Carbonyl Compounds Derivatives 2.1 Allylations 2.2 Propargylation...
Dipolar-dephasing method provides some information about the strength of dipolar coupling in solids. Dipolar dephasing technique measures the time for a polarized carbon nucleus to lose its magnetization once the proton locking field is terminated. The dynamics of guest molecules adsorbed within the cavities and channels of nonporouszeolite strongly depend on the structure and chemical composit...
Pyrinodemin A 1, a cytotoxic marine alkaloid, was synthesized in a convergent and enantioselective fashion. The key steps are an asymmetric intramolecular dipolar cycloaddition of an oxazoline N-oxide to introduce the bicyclic ring system of the molecule, a cuprate coupling for the extension of the saturated chain and a B-alkyl Suzuki coupling for the introduction of a 3-pyridyl moiety. Reducti...
The catalytic asymmetric three-component 1,3-dipolar cycloaddition of 3-amino oxindoles with aldehydes and nitroolefins under the catalysis of a chiral phosphoric acid is reported. The reaction provides a facile approach to synthesize a diverse array of spiro[pyrrolidine-2,3'-oxindoles] in high yields with excellent diastereo- and enantioselectivities under mild conditions.
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