Direct Lithiation. I

Abstract

In the previous paper,² we described the reaction of lithiated ethynyl compounds using butyllithium at -70° with lactones and sugar lactones such as 2,3 : 5, 6-di-o-isopropyl-idene-L-gulonolactone (I) or 2,3-o-isopropylidene-D-ribonolactone (II) to obtain ethynyl lactols.