HALOGENOVINYL SULFONES - 6 - 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 die ne moiety were prepared from L-amino acid as chiral building blocks. I ntramolecular Diels-Alder reaction of the sulfonyl trienes having E-ge ometry on the diene moiety proceeded on the si-face and exo-selectivel y to give cis-isoindoles as a sole product in good yields. But using t he sulfonyl trienes having Z-geometry on the diene part, the ratio of the diastereomers of the products decreased to about 80:20. The observ ed stereoselectivity can be explained by calculations with semiempiric al and ab initio methods.