Total Synthesis of (Nor)illudalane Sesquiterpenes Based on a C(sp)-H Activation Strategy.

Three (nor)illudalane sesquiterpenes were synthesized from a common intermediate in racemic and enantioenriched forms using Pd-catalyzed C(sp)-H arylation as a key step. The configuration of the isolated, highly symmetric quaternary stereocenter of the target molecules was controlled through a matched combination of chiral substrate and catalyst. Moreover, the recently developed Ir-catalyzed C-H borylation/Cu-catalyzed methylation method was employed to install the methyl group on the benzene ring. This strategy allowed the efficient synthesis of both racemic and ()-configured puraquinonic acid, deliquinone, and russujaponol F.