A new access to beta-methyl substituted secondary alcohols. Application tothe synthesis of 4-methylheptan-3-ol

All four stereoisomers of 4-methylheptan-3-ol were synthesized by a five-st ep route starting from 4-thianones. Key steps in the synthesis include: (a) reduction of 3-propyl-4-thianone to yield an easily separable isomeric mix ture of cis- and trans-3-propyl-4-thianols; and (b) a highly efficient reso lution of the particular cis/trans-isomers through a chromatographic separa tion of their respective esters with (S)-chlorofluoroacetic acid. Subsequen t hydrolysis and desulfurization gave the required compounds in 18% overall yield. All the stereoisomers are obtained with purities better than 90%. ( C) 1999 Elsevier Science Ltd. All rights reserved.