NEW DIELS-ALDER REACTIONS OF (-)-THEBAINE AND FIRST X-RAY CRYSTALLOGRAPHIC STRUCTURE ANALYSES OF THE CYCLOADDUCTS

Diels-Alder reactions of (-)-thebaine (1) as an electron-rich diene sy stem with acceptor-substituted ethenes gave rise to the cycloadducts 2 , 3, and 3 in high regio- and stereoselectivities. Structural analyses were performed by high resolution NMR spectroscopy and, for the first time in the thebaine cycloadduct series, by X-ray crystallographic st ructural analyses of the compounds 2, 3a, and 3b. In the reaction of ( -)-thebaine (1) with an in situ generated aryne, the anellated azocine derivative 5 was formed.