A Novel Skeletal Rearrangement of 2-Azabicyclo[2.2.1]hept-5-ene-3-carboxylic Acid Derivatives into 2-Oxabicyclo[3.3.0]-oct-7-en-3-ones under Acidic Conditions
作者:Tomoshige Kobayashi、Katsuhiko Ono、Hiroshi Kato
DOI:10.1246/bcsj.65.61
日期:1992.1
The reaction of ethyl 2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate with aroyl chloride and the subsequent hydrolysis of the ester group provided 2-aroyl-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylic acid derivatives, which underwent a stereospecific rearrangement giving 4-aroylamino-2-oxabicyclo[3.3.0]oct-7-en-3-ones by treatment with trifluoroacetic acid. On the other hand, the reaction of 2-benzoyl-2-azabicyclo[2.2.1]hept-5-ene with trifluoroacetic acid in heated benzene afforded 1-[(benzoylamino)methyl]-1,3-cyclopentadiene which afforded a Diels–Alder cycloadduct with N-phenylmaleimide. A plausible mechanism for the rearrangement is presented.
2-氮杂双环[2.2.1]庚-5-烯-3-羧酸乙酯与芳基氯的反应以及随后酯基的水解反应产生了2-芳基-2-氮杂双环[2.2.1]庚-5-烯-3-羧酸衍生物,这些衍生物通过三氟乙酸处理后发生立体选择性重排,生成4-芳基氨基-2-氧杂双环[3.3.0]辛-7-烯-3-酮。另一方面,2-苯甲酰基-2-氮杂双环[2.2.1]庚-5-烯与三氟乙酸在加热苯中的反应生成1-[(苯甲酰氨基)甲基]-1,3-环戊二烯,后者与N-苯基马来酰亚胺形成Diels-Alder环加成物。本文提出了一个合理的重排机制。