Quinol epoxides from p ‐cresol and estrone by photooxygenation and titanium(IV)‐ or vanadium(V)‐catalyzed oxygen transfer

On treatment with Ti(O i Pr) 4 , 4‐hydroperoxy‐4‐methyl‐2,5‐cyclohexadien‐1‐one ( 1 ) and 10β‐hydroperoxy‐1,4‐estradiene‐3,17‐dione ( 3 ), readily available by photooxygenation of p ‐cresol and estrone, respectively, were converted to the corresponding epoxy quinols 5 and 6a, b . Also significant amounts of the respective quinols 2 and 4 were obtained, which could be transformed in high yields into 5 and 6a, b by Sharpless oxidation with tert ‐butyl hydroperoxide using Ti(O i Pr) 4 or VO(acac) 2 as catalysts. Epoxidation of the quinol 4 with m ‐CPBA led preferentially to the lactone 7 by Bayer‐Villiger rearrangement, showing the advantage of the present synthetic method.