Pd-Catalyzed Three-Component Chemospecific Allylic Substitution Cascade for the Synthesis of N-Carbonylmethylene-2-Pyridones
نویسندگان
چکیده
منابع مشابه
Pd-catalyzed enantioselective allylic substitution: new strategic options for the total synthesis of natural products.
The enantioselective version of palladium-catalyzed allylic substitution, sometimes referred to as AAA (asymmetric allylic alkylation), has emerged as a powerful synthetic tool.[1] Since the first report of a stoichiometric AAA reaction in the 1970s,[2] it took almost 20 years of research until effective catalytic systems based on chiral ligands were developed. The major challenge in conducting...
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We present a mechanistic investigation of Pd-catalyzed allylic substitution of cyclic gem-difluorinated carbonates 1 and 4, previously employed in the synthesis of 3',3'-difluoro-2'-hydroxymethyl-4',5'-unsaturated carbocyclic nucleosides in 17 steps. The substitution features a reversal of regioselectivity caused by fluorine.
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Enantiomerically pure alkoxypyrrolinones have been shown to be facile building blocks for a variety of stereoselective syntheses involving Diels-Alder cycloadditions , 1,3dipolar reactions, conjugate additions, and acyliminium ion intermediates. In particular the application in the asymmetric synthesis of alkaloids based on N-acyliminium ion chemistry is of current interest. For example, (R)-1-...
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Enantioselective allylic substitution catalyzed by transitionmetal complexes is an important process in organic synthesis. For many years, mainly palladium complexes that contain chiral ligands have been employed as efficient catalysts in these reactions. Recent studies have demonstrated that chiral catalysts based on other transition metals show different regioselectivity in the synthesis of b...
متن کاملNickel-catalyzed allylic substitution of simple alkenes.
Nickel-catalyzed intermolecular allylic substitution of simple alkenes (ethylene and alpha olefins) is described. This method is the first catalytic intermolecular process for direct allylation of nonconjugated, nonstrained simple alkenes. Catalyst loadings as low as 2.5 mol % Ni afford the desired product in high yield in both gram-scale and smaller scale coupling reactions.
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ژورنال
عنوان ژورنال: Acta Chimica Sinica
سال: 2019
ISSN: 0567-7351
DOI: 10.6023/a19060210