Stereoselective condensation of bis-p-tolylthiomethane with lactic acid derivatives through an acylation–reduction strategy: synthesis of protected 4-deoxy-L-threose and 4-deoxy-L-erythrose

Abstract

The condensation of lithium bis-p-tolylthiomethanide with protected ethyl-L-lactates gave a series of 3-alkoxy-(or 3-hydroxy-) 1, 1-bis-p-tolylthiobutan-2-ones, which were stereoselectively reduced to the corresponding syn- or anti-alcohols with diastereoselectivities of up to 85:15 and 75:25, respectively. These alcohols were then converted into variously protected 4-deoxy-L-threose and 4-deoxy-L-erythrose derivatives.