Synthesis of an Optically Active Trisubstituted α,β-Butenolide, (S)-4, 6-Dihydroxy-2, 3-dimethyl-2-hexesoic Acid 1, 4-Lactone, from 2-Deoxy-D-ribose

The title compound has been synthesized efficiently from 2-deoxy-D-ribose. The synthesis involves : 1) an aldol like carbon-carbcr. bond formation of (S)-3, 5-dibenzyioxy-2-pentanor.e ( 8 ) with a lithium enolate of methyl propanoate, and 2) O -de-benzylation of the aldol adducts ( 11 ) for a γ-lactonization followed by β-elimination of the desired butenolide skeleton.