Convenient Construction of Indanedione-Fused 2,5-Dihydropyridines, 4,5-Dihydropyridines, and Spirooxindolines
文摘
A cycloaddition reaction promoted by the Lewis acid BF3·OEt2 between 2-arylidene-1,3-indanediones and β-enamino esters, generated by the addition of arylamines to dimethyl acetylenedicarboxylate, gave densely substituted 1,4-diphenyl-4,5-dihydro-1H-indeno[1,2-b]pyridines in satisfactory yields. When 2-isatylidene-1,3-indanediones were used under the same conditions, the one-pot reaction gave the corresponding spiro[indeno[1,2-b]pyridine-4,3′-indolines] in high yields. On the other hand, unusual 1,2-diphenyl-2,5-dihydro-1H-indeno[1,2-b]pyridines were obtained in moderate to good yields through a four-component reaction.