Lithium derivatives from enatiomerically pure 2-(2'-haloethyl) dioxolanes: Formation and use as chiral propanol homoenolate synthons

Article abstract of DOI:10.1016/0957-4166(95)00225-E

Condensation of acetals of 3-chloro- and 3-bromopropanal with (-)-1,4-di-O-benzyl-L-threitol and (-)-cis-2,3-bornanediol leads to the corresponding 2-(2'-chloroethyl-)- and 2-(2'-bromoethyl)dioxolanes that were converted into the Li-derivatives by transhalometallation with t-butyllithium in excellent yields. These chiral propanol homoenolates react with benzaldehyde and acetophenone yielding carbinols in moderate chemical yields and low diastereomeric excesses.