BIOCATALYSIS AS A USEFUL TOOL IN PHEROMONE SYNTHESIS - ENANTIOMERICALLY PURE BUILDING-BLOCKS FROM BAKERS-YEAST REDUCTIONS AND ENZYME-CATALYZED RESOLUTIONS

Biocatalytical methods are presented which provide useful building blo cks for pheromone synthesis. Examples of the utility of this approach are the preparation of building blocks for the synthesis of stereochem ically pure isomers of pine sawfly pheromones and some other pheromone s. Enantiomerically pure (> 98% ee) 2-methyl-1-alkanols 2 were obtaine d via baker's yeast reduction of suitable cr,P-unsaturated aldehydes, and by using lipases from Pseudomonas to effect resolution by transest erification of suitable racemic precursors to 2-methyl-1-alkanols 2 wh ich gave high enantiomeric ratios E > 100. The resolution by esterific ation mediated by lipase from Candida rugosa of racemic 2-methylalkano ic acids also gave high enantiomeric ratios E > 100 after having impro ved the reaction conditions by regulating water activity, by choice of the appropriate complimentary substrate alcohol and by adjusting the initial equivalents of the latter present at the start. Also discussed is the separation of diastereomers of diprionol 1, which is naturally occurring in the pine sawfly Neodiprion sertifer, where it is the dir ect precursor of its pheromone.