p-TsOH catalyzed Diels-Alder reaction of 3-(indol-3-yl)maleimides with 3-phenacylideneoxindoles in toluene at 80 °C for two hours afforded cis/trans isomers of 3a',4′,6′,10c'-tetrahydrospiro[indoline-3,5′-pyrrolo[3,4-c]carbazoles] in nearly comparable yields, which could be easily converted to the corresponding 4′,6′-dihydrospiro[indoline-3,5′-pyrrolo[3,4-c]carbazole] in high yields and with high
p-TsOH在
甲苯中于80°C催化3-(
吲哚-3-基)马来
酰亚胺与3-苯
甲叉基氧
吲哚的Diels-Alder反应2小时,得到3a',4',6',10c'-的顺式/反式异构体四氢螺[
吲哚啉-3,5'-
吡咯并[3,4-c]
咔唑]的收率几乎相当,可以轻松转化为相应的4',6'-二氢螺[
吲哚啉-3,5'-
吡咯并[3] ,4- c ]
咔唑]通过进一步的
DDQ氧化以高收率和高非对映选择性形成。此外,3-(
吲哚-3-基)马来
酰亚胺与2-亚芳基-1,3-
茚二酮在
甲苯中80°C的相似反应和顺序
DDQ氧化得到官能化的二氢螺[indene-2,5'-pyrrolo [3, 4- c ]
咔唑]为主要产品。