Substituent-controlled domino-Henry-hetero Diels–Alder reaction: synthesis of polycyclic nitronates
摘要:
Syntheses of hitherto unreported 5-aryl-3,3-dimethylchromeno[2,3-b]furo[3,4-dlpyridine-1,11-diones and 6-aryl-4,4-dimethyl-12-oxochromeno[2,3:2',3]pyridino[4',5'-d][1,2]oxazine-2-N-oxide have been accomplished by a metal-free domino-Henry-hetero Diels-Alder reaction. (C) 2013 Elsevier Ltd. All rights reserved.
通过在吡啶存在下于乙醇中加热,使2-(N-烯基-N-芳基)氨基-4-氧代-4 H -1-苯并吡喃-3-甲醛与二甲酮/麦德鲁姆酸/ 4-羟基香豆素反应生成多环一锅反应中带有吡啶和吡喃环的杂环。取代基对氨基官能团的N-原子的影响控制了反应方式。末端烯烃偏爱分子内迈克尔型反应,但非末端烯烃偏爱Diels-Alder反应,而在类似条件下,2-(N-烷基-N-烯丙基)氨基-4-氧代-4 H -1-苯并吡喃-3 -甲醛经历多米诺-Knoevenagel-杂Diels-Alder反应。
2-(N-Alkenyl-N-aryl)aminochromone-3-carbaldehyde undergoes intramolecular Povarov reaction with aromatic amines in the presence of Ph3P·HClO4 to produce chromenonaphthyridine. The effects of substituent and catalyst have been studied. The substituent on the alkenyl part of aminochromone controls the mode of reaction as well as the stereochemistry of the product.