Bisallylic alcohols synthesis

Double Sharpless epoxidation was also applied to the synthesis of a key intermediate 10 to the meso-compound 11 that is related to teurilene, abioactive polycyclic triterpene isolated from red alga Laurencia obtusa,4 The reaction of ( , )-Bisallylic alcohol 9 gave the bisglycidic alcohol 10 with 80% de and 89% ee for each epoxidation (Scheme 6AA.4). 

Similarly, the selective epoxidation of the bisallylic alcohol (XII) to the bis-epoxyalcohol (XIII), with (-Bu02 H-VO(acac)2, is the crucial step in a synthesis of juvenile hormone from farnesol467 ... 

The first examples of intramolecular AHRs were reported by Shibasaki et al. [123] and Overman et al. [124] in 1989. The Shibasaki group carried out cycliza-tion of achiral alkenyl iodide or triflate 300 to give the chiral tetrahydronaph-thalene system 301 by differentiation of enantiotopic C=C double bonds using (i )-BINAP without using a silver salt [123]. Subsequently, the reaction has been improved [125]. The chiral hexahydronaphthalene system 304 with 86% ee was obtained by AHR of the bisallylic alcohol 302 via syn j6-H elimination from the intermediate 303, and 304 was converted to the key intermediate 305 in the synthesis of vemolepin (306). Use of a mixed solvent of 1,2-dichloroethane and r-BuOH is important [126]. 

---