Enantiospecific Synthesis of (+)-(2R)- and (-)-(2S)-6-Ethyl-3,4-dihydro-2-methyl-4-oxo-2H-pyran-5-carboxylic Acid

Article abstract of DOI:10.1002/hlca.19890720413

The two enantiomers (-)-(2S)- and (+)-(2R)-6-ethyl-3,4-dihydro-2-methyl-4-oxo-2H-pyran-5-carboxylic acid ((S)- and (R)-7) have been synthesized from (+)-(3S) and (-)-(3R)-3-hydroxybutanoates, respectively (Scheme 1).By reduction and decarboxylation, the tetrahydro-2H-pyranols (2R,4R,6S)- and (2S,4S,6R)-13, respectively, were obtained with an enantiomeric excess of >/= 93 percent.