Abstract Recently there has been a great deal of interest in the preparation and use of selectively blocked quinones. Thus, Evans1 has used p-quinone monoketals and silyl cyanohydrin derivatives in synthetic studies. The parent p-benzoquinone mono (ethylene) ketal has been prepared2. Deslongchamps and co-workers3 used a spirolactone blocked o- quinone in an elegant total synthesis of ryanodol. Likewise, Wiesner4 has used a ...