HIGHLY EFFICIENT, REGIOSELECTIVE AND STEREOSELECTIVE RING-OPENING OF EPOXIDES AND THIIRANES WITH CE(OTF)(4)

Ceric triflate, Ce(OTf)(4) is used as an efficient catalyst for ring o pening of epoxides in the presence of alcohols, water, and acetic acid . The reactions proceed with high regio and stereoselectivity and in e xcellent yields. The reaction of R(+) styrene oxide with methanol occu rs with excellent optical purity. Ring opening of thiiranes in alcohol s, water and acetic acid followed by dimerisation to the corresponding disulfides occur efficiently in the presence of this reagent. A mild method for the preparation of dithianes from thiiranes and Ce(OTf)(4) is also described.