Divergent enantioselective synthesis of (P)- and (M)-dihydro[5]helicenequinones from a common tetrahydroaromatic precursor

The domino asymmetric Diels-Alder reaction/spontaneous sulfoxide elimination process between a vinyl dihydrophenanthrene as diene and enantiopure (SS)-2-(p-tolylsulfinyl) 1,4- benzoquinone gave access to a tetrahydroaromatic pentacyclic derivative possessing central chirality which led, in a divergent way, to helically chiral (P) or (M) enantiomers of dihydro[ 5]helicenequinones in good to excellent chemical and optical yields simply by selecting the appropriate oxidant reagent which makes the final aromatization.