Pericyclic Transformations at the Periphery of Chromen-4-one (=4H-1-Benzopyran-4-one): An Unusual Preference for a 1,5-Shift of Allylic Moieties over the Ene Reaction
作者:Gurmit Singh、Gurpinder Singh、Mohan Paul S. Ishar
DOI:10.1002/hlca.200390008
日期:2003.1
cinnamyl), which is followed by intramolecular cyclization involving the N-atom and the ester function, to give the 3-allyl-3-crotyl-, and 3-cinnamyl-substituted-1-phenyl- or 1-benzyl-2H-[1]benzopyrano[2,3-b]pyridine-2,5(1H)-diones 10a–c and 17a–c. The anticipated carbonyl–ene reaction in the 2-(N-allylanilino)-, 2-(N-crotylanilino)-, 2-(N-cinnamylanilino)-, 2-[allyl(benzyl)amino]-, 2-[benzyl(crotyl)amino]-
与许多相关杂环系统外围易反应的烯反应完全不同,在铬烯-4-酮(= 4 H -1-苯并吡喃-4-酮)体系的外围类似布置的部分无法进行烯反应,并且对烯丙基C原子的整体[1,5]位移表现出相当不寻常的偏好。因此,加热2-(N-烯丙胺基)-,2-(N- crotylanilino)-和2-(N-肉桂基氨基)-取代的(E)-(氧代色烯基)丙酸酯9a - c和2- [烯丙基(苄基氨基)-,2- [苄基(巴豆基)氨基]-和2- [苄基(肉桂基)氨基]-取代的(E)-(氧代色烯基)丙酸酯16a –c在220-230°的密封管中导致烯丙基部分(烯丙基,巴豆基,肉桂基)发生[1,5]转移,然后进行涉及N原子和酯官能团的分子内环化反应,从而得到3-烯丙基-3-巴豆基和3-肉桂基取代的1-苯基-或1-苄基-2 H- [1]苯并吡喃并[2,3 - b ]吡啶-2,5(1 H)-二酮10a – c和17a – c。2-(N