Effect of the Nature of Surfactant on the Reactivity of C,N-diphenylnitrone towards Acrylonitrile in Different Microemulsions Systems

The present work provides an insight into the effect of the nature of surfactant (cationic, anionic), a component of water- and oil-borne microemulsions, on the reaction rate of 1,3-dipolar cycloaddition of C,N-diphenylnitrone with acrylonitrile. The electrostatically attractive character of the cationic surfactant, would bring the reactants closer to each other; hence, a rate enhancement would ensue, particularly within the water-rich zone. Besides the fact that acrylonitrile played a dual role, as a component of the microemulsion and a dipolarphile in the cycloaddition reaction, made the work-up advantageously sound. Additionally, the increase in reagents molar ratio was found to promote higher reactivity

Unexpected boratranes: BBr3 mediated synthesis and mechanistic insights

International audienceBoratranes synthesis are predictably based on the reactions of triethanolamine derivatives with boric acid, or trialkyl borate and require prolonged heating of the reagents under reflux. Herein, the authors report an efficient synthesis of unexpected boratranes featuring on one hand three six-membered chelating ring or two six-membered and one five-membered chelating ring and on the other hand a trans-annular boron atom is bound to one nitrogen, two oxygen and one carbon atom. These novel boratranes have been synthetized by reacting N,N-bis(2-methoxybenzyl) alkynylamines with BBr3 in dichloromethane at low temperature. The reaction mechanism was investigated by using density functional theory (DFT) calculations. A mechanistic pathway proceeding through a key dioxazaborecinium intermediate was proposed. This alternative protocol represents a convenient access to dissymmetric and functionalizable boratranes under mild conditions in good yields