Calix[n]arene-catalyzed three-component povarov reaction: microwave-assisted synthesis of Julolidines and mechanistic insights

• Autor(es): Abranches, Paula Aline da Silva ; Paiva, Walysson Ferreira de ; Fátima, Angelo de ; Martins, Felipe Terra ; Fernandes, Sergio Antonio
• Data: 2018
• Origem: Oasisbr
• Assunto(s): Povarov reaction; Calix[n]arene-catalyzed
• Tipo de Documento: Artigo científico
• Idioma: Inglês

Descrição

A 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.