Several dienes, synthesized from cyclic enol-ethers, were opposed to a
lpha-phenyl or alpha-alkyl sulfinylalkenones in Diels-Alder reactions.
alpha-Phenylsulfinylalkenones gave unstable adducts which spontaneous
ly lost phenylsulfenic acid, while the other dienophiles led to stable
adducts in the form of diastereoisomeric mixtures.