Trisubstituted olefins, activated with I2, are changed into iodohydrins and epoxides by pyridinium dichromate. The conversion shows to proceed in regiospecific and stereospecific manner. Moreover some naturally occurring polyenes, submitted to similar treatment, afford selectively only terminal iodohydrins. These latter are converted into the corresponding epoxides through a new and convenient alumina supported reaction.
![6-decyl-7-oxabicyclo[4.1.0]heptane结构式](https://image.chemsrc.com/caspic/128/86976-35-4.png)