Asymmetric Diels-Alder Reactions of (S)-2-(p-Tolylsulfinyl)-1,4-naphthoquinones

Article abstract of DOI:10.1021/jo00051a036

The asymmetric Diels-Alder reactions of (S)-2-(p-tolylsulfinyl)-1,4-naphthoquinones 1a-c with cyclic dienes have been explored.The high ? facial diastereoselectivity observed can be reversed in the presence of ZnBr2.Evidence is presented to show that the regiochemical outcome of these reactions is controlled only by the sulfinyl group.The in situ cycloaddition/pyrolytic sulfoxide elimination starting from chiral 1a-c offers a convenient new route for the construction of enantiomerically pure 1,4-dihydro-9,10-anthraquinones (+)-10 and (+)-12a-c.