Various 5-methoxy-pentono-1, 4-lactones and derivatives thereof were synthesised from propargyl alcohol or its methyl ether. The key step was the enantioselective reduction of 2- oxo-5-alkoxy-3-pentenoic acids by resting cells of Proteus vulgaris. The (R)-2-hydroxy-5- methoxy-3-pentenoic acid (ee.> 96%) was further functionalized via epoxidation, or hydroxylation with osmium tetroxide, or bromine addition, with modest to good ...
