نتایج جستجو برای: cycloadditions
تعداد نتایج: 1035 فیلتر نتایج به سال:
2-Isoxazolines represent a well known class of heterocycles, readily accessible in particular by 1,3-dipolar cycloaddition of nitrile oxides to alkenes. 2-Isoxazolines are easily transformed into 2isoxazolinium salts by N-methylation, and further into 3-isoxazolines by deprotonation. In contrast to the parent system, less is known concerning the chemistry of the derived classes, and potential a...
Azaoxyallyl cations represent a family of versatile and powerful synthetic synthons, which are generally in situ generated from a-halohydroxamates in the presence of organic or inorganic bases. Owing to the unique structural features and reactivities of azaoxyallyl cations, some various efforts have been made to enrich the synthetic methodology of azaoxyallyl cations (Scheme 1, 1). In 2011, Jef...
This review covers articles published in the period from 2010 to mid-2022 on synthetic advances formation of pyrimidine and related heterocyclic compounds. Special emphasis has been given different types cycloadditions, taking into account number their components leading ring. Due large publications Biginelli reaction reactions, this will be dealt with a separate near future.
Abstract One-pot two sequential [3 + 2] cycloadditions of azomethine ylides with different dipolarophiles for diastereoselective synthesis spirooxindole pyrrolizidines are introduced. This one-pot involving five components generates a highly condensed ring system bearing seven stereocenters diastereoselectively. The new method has high pot, atom, and step economy. Only equivalents water release...
Cycloadditions are among the most trusted of chemical transformations available to the synthetic chemist. The predictability of the transition state based on steric and electronic considerations allows for the strategic construction of complex molecular assemblies. While the Diels–Alder reaction has received the most attention, 1,3-dipolar cycloadditions have also maintained a place of prominen...
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