The Fráter-Seebach alkylation

beta-hydroxy esters using superbases such as LDA or LiHMDS.

This organic reaction was first reported by G. Fráter in 1979 (DOI DOI).

In the original Fráter publication the starting material is ethyl acetoacetate 1, stereoselectively converted to the beta-hydroxy ester 2 with Baker’s yeast, converted to the dianion 3 with LDA and finally alkylated with iodomethanein HMPA to 4.