No abstract

Sulfinyltoluquinones (2a–2c) were submitted to thermal or catalyzed [4+2] cycloaddition reactions with cyclopentadiene. For p-tolylsulfinyltoluquinones (2b) and (2c), almost complete C2–C3-chemo- and unlike-diastereoselectivity was achieved by catalysis with ZnBr2, yielding adducts 6. Under thermal conditions, Diels–Alder reaction took place at the C5–C6 double bonds of quinones 2a–2c, generating mixtures of diastereoisomeric like- and unlike-adducts 4.

The structure analysis of the title compound, C14H16O2S2, shows the SMe and H atoms of the bond linking the six-membered rings to be syn and also to be syn to the bridgehead –CH2– group. Each of the five-membered rings adopts an envelope conformation at the bridgehead –CH2– group. The dione-substituted ring adopts a folded conformation about the 1,4-C⋯C vector, with the ketone groups lying to one side. The cyclo­hexene ring adopts a boat conformation.

Toluquinone–cyclopentadiene Diels–Alder epoxide adducts react with sulfur and oxygen nucleophiles under heterogeneous conditions, leading to products resulting from the epoxide ring opening and from skeletal rearrangement, respectively. Pyrolysis of the sulfanyl adducts gave the new 3-sulfanyltoluquinones (1).