A practical and efficient procedure for reduction of carboxylic acids and their derivatives: use of KBH4–MgCl2

The use of KBH4–MgCl2 to reduce carboxylic acids and their derivatives to the corresponding alcohols or the respective reduced products is described. Methyl (S)-3,4-O-isopropylidene-3,4-dihydroxy butanoate 2 used as a reference substrate was reduced with KBH4 and MgCl2 in 1:1 mol ratio to (S)-1,2-O-isopropylidene-1,2,4-butanetriol 1.