An efficient approach for the copper-catalyzed regioselective tandem synthesis of diversely substituted indolo[2,1-a]isoquinolines 11a-r, pyrrolo[2,1-a]isoquinolines 12a-d, and indolo-, pyrrolo[2,1-f][1,6]naphthyridines 14a-f via preferential addition of the heterocyclic amines onto the ortho-haloarylalkynes over N-arylation followed by intramolecular C-2 arylation is described. The scope of the developed chemistry was successfully extended for the direct synthesis of bisindolo-, pyrrolo[2,1-a]isoquinolines 15a-g, a regioisomer of the bisindolo[1,2-a]quinolines used as organic single-crystal field-effect transistor. Hydroxymethyl benzotriazole, which is an inexpensive and air stable compound, has been used as a ligand to carry out this one-step conversion of simple, readily available starting materials into an interesting class of heterocyclic compounds.
A novel Pd(II)-catalyzed approach for the direct synthesis of differentially substituted carbazoles from free (NH) indoles via regioselective triple successive oxidative Heck (Fujiwara-Moritani reaction) has been achieved. It is demonstrated that both electron-deficient and electron-rich alkenes could be used successively for the incorporation of two different functional groups into the product. The proposed mechanistic pathway was well supported by isolating the first and second successive oxidative Heck intermediates as well as by trapping with styrene-d3.
Efficient, step-economic, Pd(ii)-catalyzed one-pot sequential Sonogashira/Sonogashira, Sonogashira/Suzuki, Sonogashira/Heck, Suzuki/Sonogashira, Suzuki/Suzuki, Suzuki/Heck, Heck/Sonogashira, Heck/Suzuki and Heck/Heck cross coupling reactions of sterically hindered aryl/heteroaryl 1,2-dihalides have been developed. The present methodology allows the conversion of easily available aryl/heteroaryl 1,2-dihalides into synthetically useful unsymmetrically substituted arenes/heteroarenes in good to excellent yields under mild reaction conditions. This methodology is a powerful tool for building a versatile substrate which can be utilized for the synthesis of various organic scaffolds.
A novel Pd(II)-catalyzed approach for the direct synthesis of highly functionalized carbazoles from unprotected styrylindoles has been developed. The reaction features a variety of olefin substrates, which are readily switchable by subtle tuning of the reaction conditions. Investigations of the mechanism suggest that the C-H activation proceeds via enamine formation.
A new class of bidentate ligand, 1-(pyridine-2-yl)-1H-benzo [d]A C H T U N G T R E N N U N G [1,2,3]triazole has been designed and employed for the palladium-catalyzed C À C (Suzuki, Heck, Fujiwara-Moritani, and Sonogashira), C À N and C À S coupling reactions. The ligand was found to be inexpensive, thermally stable, easy to synthesize from easily accessible starting materials on a multigram scale, show simplicity in use, and robustness in application, making this ligand effective for different coupling reactions. Suitably, the donor ability of the N=N bond of the benzotriazole ring and lone pair of electrons on the N of the pyridine ring enhance the bidentate ability of the ligand.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.