Wang Lun, Liu Lingyan, Chang Weixing, Li Jing
The State Key Laboratory and Institute of Elemento-Organic Chemistry, the College of Chemistry , Nankai University , Tianjin 300071 , China.
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Weijin Road 94 , Nankai District, Tianjin 300071 , China.
J Org Chem. 2018 Aug 3;83(15):7799-7813. doi: 10.1021/acs.joc.8b00691. Epub 2018 Jun 18.
Two divergent cascade reactions of arylalkynols with homopropargylic amines or electron-deficient olefins were developed to synthesize the spiro-isobenzofuran- b-pyrroloquinolines or bridged-isobenzofuran heterocycles in good yields, respectively. One reaction actually involved intramolecular 5- endo-dig hydroamination cyclization-protonation of homopropargylic amines to give cycloiminium ions and intramolecular 5- exo-dig hydroalkoxylation cyclization of arylalkynols to generate isobenzofuran with exocyclic double bond, followed by the nontypical Povarov-type reaction in the presence of PtCl/FeCl cocatalysts. The other underwent intramolecular hydroalkoxylation cycloisomerization of alkynols with the subsequent normal [4 + 2] cycoaddition with dienophiles. Herein, the arylalkynols acted as both "masked" electron-rich olefins and "masked" electron-rich dienes.
开发了芳基炔醇与高炔丙基胺或缺电子烯烃的两种不同的级联反应，分别以良好的产率合成了螺异苯并呋喃-γ-吡咯并喹啉或桥连异苯并呋喃杂环。其中一个反应实际上涉及高炔丙基胺的分子内5-endo-dig氢胺化环化-质子化以生成环亚胺离子，以及芳基炔醇的分子内5-exo-dig氢烷氧基化环化以生成具有环外双键的异苯并呋喃，随后在PtCl/FeCl共催化剂存在下进行非典型的Povarov型反应。另一个反应是炔醇的分子内氢烷氧基化环异构化，随后与亲双烯体进行正常的[4 + 2]环加成反应。在此，芳基炔醇既充当“掩蔽”的富电子烯烃，又充当“掩蔽”的富电子二烯。
