Heterodienophilic intramolecular diels-alder reactions of 1,2,4 triazines.
作者:Edward C. Taylor、Joseph L. Pont、John C. Warner
DOI:10.1016/s0040-4020(01)87691-2
日期:1987.1
7-(2'-cyanophenoxy)-6-azalumazines undergo intramolecular Diels-Alder reactions to yield novel polycyclic pyrazines and lumazines. However, the analogous 5-(2'-cyanophenoxy)-1,2,4-triazines fail to undergo cycloaddition, preventing access to the unknown benzfuro[2,3-]-1,2,4-triazine system. Substitution of oxime ethers for nitriles on the dienophilic sidechains of the respective Diels-Alder precursors failed to increase
-3-(2'-氰基苯氧基)-1,2,4-三嗪和7-(2'-氰基苯氧基)-6-azalumazines经历分子内Diels-Alder反应生成新的多环吡嗪和lumazines。但是,类似的5-(2'-氰基苯氧基)-1,2,4-三嗪无法进行环加成反应,从而无法进入未知的苯并[2,3- ]- 1,1,2,4-三嗪系统。肟醚被相应的Diels-Alder前体的亲二烯键侧链上的腈取代无法提高其逆电子需求Diels-Alder反应性。