Biosynthesis of sex pheromones in moths: stereochemistry of fatty alcohol oxidation in Manduca sexta

Six chiral deuterium labelled metabolic probes, (R) and (S)-enantiomers of [1,10,10-2H3]-hexadecan-1-ol, (11E)-[1,10,10-2H3]-hexadec-11-en-1-ol and (11Z)-[1,10,10-2H3]-hexadec-11-en-1-ol, were synthesized to examine the stereospecificity of the fatty alcohol oxidase from the female pheromone gland of the tobacco hawk moth (Manduca sexta, Sphingidae). Both in vitro and in vivo oxidations were found to proceed by selective removal of the C1–HR hydrogen or deuterium atom (Re-specificity) to yield the corresponding aldehydes. (R) and (S)-enantiomers of deuterium labelled salicyl alcohol and 2-thienyl-methanol, compounds entirely chemically diverse from the natural pheromone precursors, were also oxidised Re-specifically to salicylaldehyde and 2-thiophenecarb-aldehyde, respectively.