In an attempt to explore the effect of the ester group at C4, triene 14 11 was submitted to the above-described conditions. As in preceding examples, oxidation of 14 with m-CPBA at 0 °C in CH 2 Cl 2 and saturated aqueous NaHCO 3 was chemo- and stereoselective producing a mixture of two diastereomeric epoxides 15a and 15b as deduced from NMR spectra. However, treatment of the crude epoxide with allyl alcohol in the presence of catalytic Yb( ...
