Furanyl spiroketals as stereochemical relays in the synthesis of 1,9-anti diols: synthesis of insect pheromones

A suite of spiroketal insect pheromones (15 and 17a-d) has been synthesised in good yield and with very high levels of diastereoselectivity via furanyl spiroketals. Remote asymmetric induction is achieved under thermodynamic control. The use of furanyl spiroketals as temporary scaffolds in the synthesis of 1,9-anti diols has been demonstrated with the synthesis of the swede midge pheromone (2S,10S)-2,10-diacetoxyundecane 1. The enzymatic resolution of a C2 symmetric 1,9-anti diol was used as a confirmation of diastereomeric purity.