The reaction of 2-(N-alkenyl-N-aryl)amino-4-oxo-4H-1-benzopyran-3-carbaldehyde with dimedone/Meldrum’s acid/4-hydroxycoumarin by heating in ethanol in the presence of pyridine produces polycyclicheterocycles bearing pyridine and pyran rings in a one-pot reaction. The effect of substituents on N-atom of the amino function controls the mode of reaction. Terminal alkenes prefer intramolecular Michael
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。
Regio- and stereoselective synthesis of 1-benzopyrano[2,3-b]pyrrolo[2,3-d]pyridines: A microwave-accelerated intramolecular [3+2] cycloaddition reaction of azomethine ylide
作者:Sourav Maiti、T. M. Lakshmykanth、Suman Kalyan Panja、Ranjan Mukhopadhyay、Ayan Datta、Chandrakanta Bandyopadhyay
DOI:10.1002/jhet.567
日期:2011.7
Regio‐ and stereoselective syntheses of tetracyclic compounds having chromone, pyrrolidine, and piperidine rings have been accomplished by an intramolecular [3+2] cycloadditionreaction involving azomethineylide. The reactions were carried out thermally as well as by irradiation with microwave. The latter process accelerates the reaction. The selectivities were investigated by density functional theory