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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11800
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Item Calix[n]arene-catalyzed three-component povarov reaction: microwave-assisted synthesis of Julolidines and mechanistic insights(The Journal of Organic Chemistry, 2018-01-16) Abranches, Paula Aline da Silva; Paiva, Walysson Ferreira de; Fátima, Angelo de; Martins, Felipe Terra; Fernandes, Sergio AntonioA new one-pot cascade reaction-based application of Povarov reactions with a p-sulfonic acid calix[4]arene catalyst for the synthesis of a series of 34 julolidine derivatives with substituents at C8 or C9 in good to excellent yields is reported. These microwave-assisted reactions proceeded efficiently, had short reaction times, were metal-free, were low cost, and used an inexpensive, easily available and nontoxic catalyst. These advantages, along with a simple workup procedure, make this protocol a very efficient and green alternative to the traditional methods for constructing these types of N- heterocyclic skeletons. In addition, this protocol allows the formation of julolidine structures, which requires the construction of four new C−C bonds and two C−N bonds. A mechanism for the Povarov reaction involving a stepwise sequence via ionic intermediates was proposed and validated.