Halogenovinyl Sulfones. 6.1 Synthesis of Condensed Heterocycles by Diastereoselective Intramolecular Diels−Alder Reactions of Sulfonyl-Substituted Trienes

Sulfonyl trienes having a chiral center on the allyl carbon of the diene moiety were prepared from L-amino acid as chiral building blocks. Intramolecular Diels-Alder reaction of the sulfonyl trienes having E-geometry on the diene moiety proceeded on the si-face and exo-selectively to give cis-isoindoles as a sole product in good yields. But using the sulfonyl trienes having Z-geometry on the diene part, the ratio of the diastereomers of the products decreased to about 80:20. The observed stereoselectivity can be explained by calculations with semiempirical and ab initio methods.