(3aR,7aS)-4-(2-Azidoethyl)-2,2-dimethyl-3a,7a-dihydrobenzo[1,3]dioxole (22) was converted in two steps to trienes23and24, which upon heating underwent intramolecular Diels-Alder reactions to give mixtures of isomeric 11,11-dimethyl-5-oxo-10,12-dioxa-4-azatetracyclo[6.5.2.01,6.09,13]pentadec-14-ene-7-carboxylates25,26and27,28, respectively. These products were separated and identified. For comparison, intermolecular Diels-Alder cycloaddition of diene22with maleic anhydride was carried out. Products of this reaction, 1-(2-azidoethyl)-4,4-dimethyl-3,5,10-trioxatetracyclo[5.5.2.02,6.08,12]tetradec-13-ene-9,11-diones (29and30) were converted to methyl ester analogues of31and32in a two-step sequence. The stereochemical outcome of these cycloadditions is discussed as well as their possible utilization in organic synthesis, especially in total synthesis of some alkaloids.
(3aR,7aS)-4-(2-叠氮乙基)-2,2-二甲基-3a,7a-二氢苯并[1,3]二噁唑 (<22>) 经过两步转化成为三烯烃23和24,加热后发生分子内Diels-Alder反应,生成异构体混合物11,11-二甲基-5-氧代-10,12-二氧-4-氮杂四环[6.5.2.0^1,6.0^9,13]十五烯-7-羧酸酯25、26和27、28。这些产物被分离并鉴定。为了比较,将双烯22与马来酸酐进行分子间Diels-Alder环加成反应。该反应产物,1-(2-叠氮乙基)-4,4-二甲基-3,5,10-三氧代四环[5.5.2.0^2,6.0^8,12]十四烯-9,11-二酮29和30被转化为31和32的甲酯类似物,经过两步序列。讨论了这些环加成的立体化学结果,以及它们在有机合成中的可能利用,特别是在一些生物碱的全合成中的应用。