title: Highly Efficient Catalysis of Retro-Claisen Reactions: From a Quinone Derivative to Functionalized Imidazolium Salts.
abstract: A new and efficient method for the preparation of several imidazolium salts containing an ester group in the C4 position of the aromatic ring through a retro-Claisen reaction pathway between a quinone derivative and several alcohols is described. This new organic transformation proceeds in the absence of a catalyst, but it is greatly catalyzed by different Lewis acids, especially with AgOAc at a very low catalyst loading and in very short reaction times. The process takes place by the nucleophilic attack of the carbonyl groups by the alcohol functionality, thus promoting a double C-C bond cleavage and C-H and C-O bond formation. This reaction represents the first example of this type between a quinone derivative and alcohols.
authors: Departamento of Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50005, Zaragoza, Spain.|Programa de Ingeniería Industrial, Facultad de Ingeniería, Corporación Universidad de la Costa (CUC), Calle 58, #55-66, 080001, Barranquilla, Colombia.
authors: Renso
authors: R
authors: Visbal
authors: Departamento of Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50005, Zaragoza, Spain.
authors: Antonio
authors: A
authors: Laguna
authors: Departamento of Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50005, Zaragoza, Spain. gimeno@unizar.es.
authors: M Concepción
authors: MC
authors: Gimeno
keywords: C−C activation; nitrogen heterocycles; retro-Claisen reaction; silver; synthetic methods