Wittig and horner-wittig coupling reactions of 2-substituted cyclic ethers and their application to spiroketal synthesis

Wittig and Horner-Wittig coupling reactions of tetrahydropyran or tetrahydrofuran 2-triphenylphosphonium salts or 2-diphenylphosphine oxides with aldehydes and lactols affords good yields of the corresponding enol ethers. In selected examples these enol ether products may be further converted to spiroketals some of which are natural pheromones derived from Dacus oleae and Paravespula vulgaris.