FIRST SYNTHESIS OF OPTICALLY PURE SELENURANES AND STEREOSELECTIVE ALKALINE-HYDROLYSIS - THEIR APPLICATION TO ASYMMETRIC [2,3]-SIGMATROPIC REARRANGEMENT OF ALLYLIC SELENOXIDES

The first synthesis of optically pure selenuranes 1 has been accomplis hed by utilizing 2-exo-hydroxy-10-bornyl group as a chiral ligand Comp lete retention of the configuration has been observed in alkaline hydr olysis of 1 to give selenoxides 2. The structure of 1 and 2 has been f ully established by X-ray crystallography. [2,3] Sigmatropic rearrange ment of allylic selenoxides 2 gave the corresponding allylic alcohols 3 with up to 88% enantiomeric excess (ee). The [2,3] sigmatropic rearr angement of allylic selenoxides 2 progresses predominantly via an endo transition state. (C) 1997 Elsevier Science Ltd.