Selective Lewis acid complexation of 2-hydroxyethyl esters using competitive Diels-Alder reactions as a mechanistic probe

Article abstract of DOI:10.1016/S0040-4020(99)01071-6

Competitive Diels-Alder reactions involving ethyl acrylate, 2- hydroxyethyl acrylate and 2-methoxyethyl acrylate indicate that certain Lewis acids (e.g. EtAlCl₂) selectively complex to the 2-hydroxyethyl ester group. Studies using ethyl 2-hydroxyethyl fumarate support these findings. ¹³C NMR spectroscopy provides some evidence regarding the nature of the interactions between 2-hydroxyethyl esters and EtAlCl₂. The influence of EtAlCl₂ on the level of diastereocontrol observed in the Diels-Alder reactions of (2R*,3R*)-2-(3-hydroxy)butyl acrylate is described. (C) 2000 Elsevier Science Ltd.