Efficient diastereoselective synthesis of α,β-dihydroxyesters from methyl phenylglyoxylate and aldehydes mediated by titanium trichloride/pyridine system

Article abstract of DOI:10.1016/0040-4020(95)00872-6

The reductive coupling of methyl phenylglyoxylate 2 with aliphatic and aromatic aldehydes 3, promoted by TiCl₃/Py system in anhydrous THF, affords α,β-dihydroxyesters 4 in good yields (60-94%) and high syn-diastereoselectivity (up to 85%). The type of ligand at the metal ion necessary to achieve a high level of diastereocontrol and the possible mechanism involved are discussed.