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Synthesis of a 7-azaindole by chichibabin cyclization: reversible base-mediated dimerization of 3-picolines.

ABSTRACT: The lithium diisopropylamide (LDA)-mediated condensation of 2-fluoro-3-picoline and benzonitrile to form 2-phenyl-7-azaindole via a Chichibabin cyclization is described. Facile dimerization of the picoline via a 1,4-addition of the incipient benzyllithium to the picoline starting material and fast 1,2-addition of LDA to benzonitrile cause the reaction to be complex. Both adducts are shown to reenter the reaction coordinate to produce the desired 7-azaindole. The solution structures of the key intermediates and the underlying reaction mechanisms are studied by a combination of IR and NMR spectroscopies.

SUBMITTER: Ma Y

PROVIDER: S-EPMC2736357 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature

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Synthesis of a 7-azaindole by chichibabin cyclization: reversible base-mediated dimerization of 3-picolines.

Ma Yun Y Breslin Sean S Keresztes Ivan I Lobkovsky Emil E Collum David B DB

The Journal of organic chemistry 20081201 24

The lithium diisopropylamide (LDA)-mediated condensation of 2-fluoro-3-picoline and benzonitrile to form 2-phenyl-7-azaindole via a Chichibabin cyclization is described. Facile dimerization of the picoline via a 1,4-addition of the incipient benzyllithium to the picoline starting material and fast 1,2-addition of LDA to benzonitrile cause the reaction to be complex. Both adducts are shown to reenter the reaction coordinate to produce the desired 7-azaindole. The solution structures of the key in ...[more]

PMID: 18707175

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