A first general and practical method for the synthesis of valuable 2-(hetero)aryl glycidic ethyl esters has been developed using commercially available reagents and a catalyst. A telescoped three-step seven-reaction process, based on a Knoevenagel/nitro-Michael/hydroxylation/double elimination/epoxidation/esterification sequence, provides the epoxides in up to 73% overall yield. This one-pot protocol features (i) aldehydes as versatile feedstocks, among the reagents used in the process; (ii) all steps proceeding at room temperature in benign solvents; and (iii) scalability of the reaction up to 5 mmol. The epoxides are elaborated to obtain new attractive β-amino α-hydroxy esters, bearing a quaternary stereocenter, including tryptamine- and morpholine-based esters.
Battaglia et al. (Mon,) studied this question.