Homologation of α-hydroxy acids to α-unsubstituted β-hydroxy carboxamides via Arndt–Eistert reaction

Here we studied the homologation of leucic and phenyl lactic acid via Wolff-rearrangement of their diazoketones to the corresponding β-hydroxy acids. This reaction requires distinct conditions to that of their amino acid analogues. The choice of the Oα-substituent can selectively direct the reaction to α-unsubstituted β-hydroxy carboxamides or (E)-α,β-unsaturated carboxamides and offers a new route from α-hydroxy acids to such compounds.