Synthesis and Diels-Alder Reactions of (S)-3-Chloro and (S)-3-Ethyl-2-p-tolylsulfinyl-1,4-benzoquinones

Article abstract of DOI:10.1016/0040-4039(94)88379-3

The synthesis of the title compounds in enantiomerically pure form is described.Their cycloadditions with cyclopentadiene and 2,3-dimethyl-1,3-butadiene in the presence of ZnBr2 take place on the unsubstituted dienophilic double bond C5-C6 giving access t