First Diels-Alder Reactions of Enantiomerically Pure 1-p-Tolylsulfinyl Dienes: Straightforward Access to Cyclohexenols through Tandem Cycloaddition/-Sigmatropic Rearrangement

Article abstract of DOI:10.1021/jo00091a035

The asymmetric Diels-Alder reactions of (R)-1-(p-tolylsulfinyl)-1,3-butadienes 3a-c with N-methylmaleimide (NMM) have been explored.The cycloadditions are stereospecific: only one endo adduct is formed, the ?-facial diastereoselectivity being controlled by the sulfoxide both in thermal and catalytic conditions.The in situ cycloaddition/sulfoxide sulfenate <2,3>-sigmatropic rearrangement starting from chiral 3a-c in the presence of an excess of NMM, which acts as thiophilic agent, provides a convenient one-step access to enantiomerically pure and all-cis functionalized cyclohexenols (-)-5a-c.