" Reagents:(a) menthol (both d and 1 isomers), Et3N;(b) DBU, THF;(c) Br,. CC1,;(d) DBU, DME. the regioselective vinylogous Reformatsky rea~ tion,~ respectively. The use of menthyl esters 1 and 2 in identical sequences was shown to have a good chiral auxiliary effect and the above reactions produced chiral vinylcyclopropanes4 or chiral 1, 3-di0ls,~ respectively. The preparation of both halo esters in the 1 series commenced with the condensation of ...