DIELS-ALDER REACTIONS OF 1,2-(1,1'-BINAPHTHALENE-2,2'-DIYLDISULFONYL)ETHYLENE WITH SYMMETRICAL AND UNSYMMETRICAL DIENES

The C2-symmetrical chiral reagent 1,2-(1,1'-binaphthalene-2,2'-diyldisulfonyl)ethylene (1) is a reactive dienophile and forms Diels-Alder adducts with symmetrical and unsymmetrical dienes. In the case of unsymmetrical dienes the reaction affords, in most cases, a single diastereomeric adduct whose stereochemistry has been determined by NMR spectroscopy and confirmed by X-ray structure determination of selected adducts. The arylsulfonyl groups can be removed with formation of a double bond, making 1 a chiral synthetic equivalent of acetylene in [4 + 2]-cycloaddition reactions. The binaphthyl auxiliary can be recovered and recycled.