396717-18-3Relevant academic research and scientific papers
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.
Synthesis of isoquinolines and pyridines by the palladium/copper-catalyzed coupling and cyclization of terminal acetylenes and unsaturated imines: The total synthesis of decumbenine B
Roesch, Kevin R.,Larock, Richard C.
, p. 86 - 94 (2007/10/03)
Monosubstituted isoquinolines and pyridines have been prepared in good to excellent yields via coupling of terminal acetylenes with the tert-butylimines of o-iodobenzaldehydes and 3-halo-2-alkenals in the presence of a palladium catalyst and subsequent copper-catalyzed cyclization of the intermediate iminoalkynes. In addition, isoquinoline heterocycles have been prepared in excellent yields via copper-catalyzed cyclization of iminoalkynes. The choice of cyclization conditions is dependent upon the nature of the terminal acetylene that is employed, as only aryl and alkenyl acetylenes cyclize under the palladium-catalyzed reaction conditions that have been developed. However, aryl-, vinylic-, and alkyl-substituted acetylenes undergo palladium-catalyzed coupling and subsequent copper-catalyzed cyclization in excellent yields. The total synthesis of the isoquinoline natural product decumbenine B has been accomplished in seven steps and 20% overall yield by employing this palladium-catalyzed coupling and cyclization methodology.
Synthesis of substituted isoquinolines by electrophilic cyclization of iminoalkynes
Huang, Qinhua,Hunter, Jack A.,Larock, Richard C.
, p. 3437 - 3444 (2007/10/03)
The tert-butylimines of o-(1-alkynyl)benzaldehydes and analogous pyridinecarbaldehydes have been cyclized under very mild reaction conditions in the presence of I2, ICl, PhSeCl, PhSCl, and p-O2-NC6H4SCl to give the corresponding halogen-, selenium-, and sulfur-containing disubstituted isoquinolines and naphthyridines, respectively. This methodology accommodates a variety of iminoalkynes and affords the anticipated heterocycles in moderate to excellent yields. Monosubstituted isoquinolines and naphthyridines have been synthesized by the metal-catalyzed ring closure of these same iminoalkynes. The silver-catalyzed ring closure is highly effective in cyclizing aryl-, alkenyl-, and alkyl-substituted iminoalkynes at 50°C.
