A Versatile Approach to Noncoded β-Hydroxy-α-amino Esters and α-Amino Acids/Esters from Morita–Baylis–Hillman Adducts

Abstract

A simple and straightforward approach to the diastereoselective synthesis of noncoded β-hydroxy-α-amino esters from Morita–Baylis–Hillman (MBH) adducts is described. The strategy is based on a one-pot sequence involving an oxidative cleavage of the double bond of silylated Morita–Baylis–Hillman adducts, followed by the reaction with hydroxylamine hydrochloride/pyridine to form oximes. The stereoselective reduction of the oximes with the mixture MoCl₅·nH₂O/NaBH₃CN led to the corresponding <i>anti</i>-β-hydroxy-α-amino esters in four steps in good overall yield and with diastereoselectivity higher than 95%. A slight modification of the synthetic approach has allowed for the racemic synthesis of a set of noncoded α-amino esters/acids and DOPA.