Famesol intramolecular epoxidation

The regioselective intramolecular epoxidation of the peroxy ester (163), which can be prepared from famesol, has been effected by treating it with Cu(OCOCT3)2 (equation S ). This reaction provides a convenient route for the preparation of the 6,7-epoxide (164), which cannot be synthesized from farnesol by conventional methods or even by template-directed epoxidation using Mo(C(5)6/rBHP. 

A very interesting way to control alkene epoxidation was introduced by Breslow and Meresca. In the steroid diene, 77, epoxidation takes place exclusively at the 4,5 double bond using Mo(CO)6 and TBHP. However, by attaching a template, as in 78, to the alcohol, the regioselectivity could be inverted so that epoxidation takes place only at the 17,20 double bond. It was concluded that the appendage did not act as a steric shield, but the remote tertiary alcohol moiety was transformed in situ to a hydroperoxide resulting in the observed selectivity by intramolecular epoxidation. This approach was then extended to other functionalized polyenes, such as famesol and geranylgeraniol. ... 

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