TITANIUM(II)-BASED Z-REDUCTION OF ALKYNES - SYNTHESES OF DEUTERIUM-LABELED LINOLENIC AND OLEIC ACIDS AND (3E,8Z,11Z)-TETRADECA-3,8,11-TRIENYL ACETATE, THE SEX-PHEROMONE OF A TOMATO PEST, SCROBIPALPULOIDES ABSOLUTA

An operationally simple Tin-mediated, stereo-and regio-specific reduct ion of isolated, conjugated and methylene 'skipped' polyynes to the co rresponding Z-polyenes in a one-pot procedure is described and applied inter alia to the syntheses of deuterium labelled linolenic and oleic acids. Final quenching with D2O (instead of H2O) results in regio-and stereo-specific Z-dideuteration of the alkyne. The synthesis of(3E,8Z ,11Z)-tetradeca-3,8,11-trienyl acetate, the major sex pheromone of Scr obipalpuloides absoluta, a destructive pest of tomatoes, and the (3Z,8 Z,11Z)-isomer, utilises this methodology in key reduction steps, and u nder-or over-reduction are negligible.