Gold‐Catalyzed Ring Expansion of Alkynyl Heterocycles through 1,2‐Migration of an Endocyclic Carbon–Heteroatom Bond |
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| Authors: | Ming Chen Ning Sun Wei Xu Jidong Zhao Gaonan Wang Prof. Yuanhong Liu |
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| Affiliation: | State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032 (P. R. China) |
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| Abstract: | A mild and efficient gold‐catalyzed oxidative ring‐expansion of a series of alkynyl heterocycles using pyridine‐N‐oxide as the oxidant has been developed, which affords highly valuable six‐ or seven‐membered heterocycles with wide functional group toleration. The reaction consists of a regioselective oxidation and a chemoselective migration of an endocyclic carbon–heteroatom bond (favored over C?H migration) with the order of migratory aptitude for carbon–heteroatom bonds being C?S>C?N>C?O. In the absence of an oxidant, polycyclic products are readily constructed through a ring‐expansion/Nazarov cyclization reaction sequence. |
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| Keywords: | alkynes gold heterocycles homogeneous catalysis ring expansion |
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