A convenient synthesis of a suitable alkene acetal (8) was accomplished as outlined in Scheme I.(&)-Methyl lactate (10) was converted to its tetrahydropyranyl ether (DHP/PPTS/CH2C12), 12 which was successively reduced to the primary alcohol 11 with lithium aluminum hydride and reoxidized with oxalyl chloride activated Me2S0I3 to give THP aldehyde 12 in 88% yield for the three~ teps.'~ J~ Exposure of 12 to the protected ...
