TRANSFORMATION OF HYDROXYCYCLOALKANONES TO OXABICYCLOALKENES

摘要

Oxabicycloalkenes, which represent anti-Bredt enol ethers, can be generated by catalytic dehydration of the hemiacetals of hydroxycycloalkanones (Method I). Another option is provided by the transformation of hydroxycycloalkanones to the corresponding 1,2,3-selenadiazoles and their thermal fragmentation on Cu powder (Method II). The intermediate hydroxycycloalkynes show a transannular addition of the OH group to the triple bond. Altogether seven new oxabicycloalk-1-enes were obtained by this methods.