The following sequence is illustrated in Scheme 2. Reac-tion of 7 with the dilithium reagent 811 furnished a mixture of the two diastereoisomers 9; this mixture was not separated because the two epimeric secondary alcohols were oxidized to a homogeneous ketone in a later step. We were not able to induce the dilithium derivative to react with (Z)- didehydroleucinal. Only the allyl esters were formed with Z amino acid chlorides. Attempts ...
