A diastereo- and enantio- selective synthesis of the (E)-alkene dipept
ide isostere of L-Ala-L-Ala from L-alanine has been developed which pr
oceeds via stereocontrolled addition of a (Z)-vinyllithium reagent fol
lowed by a [2,3]-Wittig rearrangement. The synthesis proceeds in seven
steps overall from L-alanine methyl ester. It is believed that this a
pproach will provide a fairly general and convenient route to isostere
s of a number of different dipeptides.