The synthesis of 5-substituted 6,6a-dihydroisoindolo[2,1-a]quinolin-11(5H)-ones via [4 + 2] imino-Diels–Alder cyclization from N-aryl-3-hydroxyisoindolinones and N-vinyl lactams under Lewis acid-catalysed anhydrous conditions is reported. Reactions of N-(2-substituted-aryl)-3-hydroxyisoindolinones with N-vinylpyrrolidone under identical conditions resulted in the formation of 2-(2-substitued-aryl)-3-(2-(2-oxopyrrolidin-1-yl)vinyl)isoindolin-1-one analogues indicating steric hinderance as the cause of deviation. The probable mechanism of the reaction based on the results from X-ray crystallography and molecular modelling is discussed.
报告了在路易斯酸催化的无水条件下,通过[4 + 2]亚胺-狄尔斯-阿尔德环化反应,从N-芳基-3-羟基异喹啉酮和N-乙烯基内酰胺合成5-取代-6,6a-二氢异喹诺[2,1-a]喹啉-11(5H)-酮的方法。在相同条件下,N-(2-取代-芳基)-3-羟基异喹啉酮与N-乙烯基吡咯烷酮的反应导致了2-(2-取代-芳基)-3-(2-(2-氧代吡咯烷-1-基)乙烯基)异喹啉-1-酮类似物的形成,表明立体阻碍是导致偏差的原因。基于X射线晶体学和分子建模结果,讨论了反应的可能机制。