An expansion of methodologies aimed at the formation of versatile organonitriles, via the intramolecular aminocyanation of unactivated alkenes, is herein reported. Importantly, the need for a rigid tether in these reactions has been obviated. The ease-of-synthesis and viability of substrates bearing flexible backbones has permitted for diastereoselective variants as well. We demonstrated the utility of this methodology with the formation of pyrrolidones, piperidinones, isoindolinones, and sultams. Furthermore, subsequent transformation of these motifs into medicinally relevant molecules is also demonstrated. A double crossover C-labeling experiment is consistent with a fully intramolecular cyclization mechanism. Deuterium labeling experiments support a mechanism involving syn-addition across the alkene.
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http://dx.doi.org/10.1021/jacs.8b01330 | DOI Listing |
J Am Chem Soc
March 2018
Department of Chemistry , University of Minnesota-Twin Cities, 207 Pleasant St. SE , Minneapolis , Minnesota 55455 , United States.
An expansion of methodologies aimed at the formation of versatile organonitriles, via the intramolecular aminocyanation of unactivated alkenes, is herein reported. Importantly, the need for a rigid tether in these reactions has been obviated. The ease-of-synthesis and viability of substrates bearing flexible backbones has permitted for diastereoselective variants as well.
View Article and Find Full Text PDFChem Commun (Camb)
December 2016
Department of Chemistry, National Taiwan Normal University, No. 88, Sec. 4, Ting-Zhou Road, Taipei 11677, Taiwan.
CuI-Catalyzed intramolecular aminocyanation of terminal alkynes in N-(2-ethynylphenyl)-N-sulfonylcyanamides was initiated by the formation of Cu-acetylide to trigger N-CN bond cleavage of the N-sulfonylcyanamide moiety followed by CN migration to form a β-cyano Cu-vinylidene intermediate. Subsequently, the indole ring closure furnished the corresponding 1-sulfonyl-3-cyanoindoles.
View Article and Find Full Text PDFChem Commun (Camb)
October 2015
School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, Nanjing University, 22 Hankou Road, Nanjing, Jiangsu 210093, P. R. China.
Density functional theory investigations reveal that the intramolecular additions of N-CN bonds to alkenes proceed in a novel asynchronous and concerted mechanism, while the intramolecular addition of O-CN bonds to alkenes may occur by both concerted and stepwise pathways.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
May 2014
Department of Chemistry, University of Minnesota-Twin Cities, 207 Pleasant St. SE, Minneapolis, MN 55455 (USA).
A metal-free, Lewis acid promoted intramolecular aminocyanation of alkenes was developed. B(C6F5)3 activates N-sulfonyl cyanamides, thus leading to a formal cleavage of the N-CN bonds in conjunction with vicinal addition of sulfonamide and nitrile groups across an alkene. This method enables atom-economical access to indolines and tetrahydroquinolines in excellent yields, and provides a complementary strategy for regioselective alkene difunctionalizations with sulfonamide and nitrile groups.
View Article and Find Full Text PDFJ Am Chem Soc
March 2014
Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan.
A cooperative palladium/triorganoboron catalyst to accomplish the intramolecular aminocyanation of alkenes through the cleavage of N-CN bonds is reported. 4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene (Xantphos) is found to be crucial as a ligand for palladium to effectively catalyze the transformation with high chemo- and regioselectivity. A range of substituted indolines and pyrrolidines with both tetra- or trisubstituted carbon and cyano functionalities are readily furnished by the newly developed cyanofunctionalization reaction.
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