Synthesis of a Major Component of the Pheromones of Formica rufa and Formica polyctena methyl-3-ethyl-4-methylpentanoate using 2R-bornane-10, 2-sultam as chiral auxiliary

(R) and (S) - Methyl - 3 - ethyl - 4 - methylpentanoate, one of the main co mponents of pheromones of the red wood ant (formica rufa) and the small for est ant (formica polyctena), was synthesized with asymmetric Michael additi on as key step. The enantiomeric excess of the target products is over 94%. The X- ray crystallographic data of a key immediate, N - [(3R) - 3 - ethyl - 4 - methyl valeryl] - (-) bornane - 10, 2 - sultam, is also reported. Th e mechanism of the Michael addition in the presence or absence of CuBr . Me 2S remains unknown.