111456-06-5Relevant articles and documents
Aryne [3 + 2] cycloaddition with N-sulfonylpyridinium imides and in situ generated N-sulfonylisoquinolinium imides: A potential route to pyrido[1,2-b]indazoles and indazolo[3,2-a]isoquinolines
Zhao, Jingjing,Li, Pan,Wu, Chunrui,Chen, Hongli,Ai, Wenying,Sun, Renhong,Ren, Hailong,Larock, Richard C.,Shi, Feng
supporting information; experimental part, p. 1922 - 1930 (2012/04/23)
The aryne [3 + 2] cycloaddition process with pyridinium imides breaks the aromaticity of the pyridine ring. By equipping the imide nitrogen with a sulfonyl group, the intermediate readily eliminates a sulfinate anion to restore the aromaticity, leading to the formation of pyrido[1,2-b]indazoles. The scope and limitation of this reaction are discussed. As an extension of this chemistry, N-tosylisoquinolinium imides, generated in situ from N′-(2-alkynylbenzylidene)-tosylhydrazides via an AgOTf-catalyzed 6-endo-dig electrophilic cyclization, readily undergo aryne [3 + 2] cycloaddition to afford indazolo[3,2-a]-isoquinolines in the same pot, offering a highly efficient route to these potential anticancer agents.
