3,4-Dihydro-2H-pyrrole-2-carbonitriles: Useful Intermediates in the Synthesis of Fused Pyrroles and 2,2′-Bipyrroles

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• 作者：Marco M. Nebe ; Murat Kucukdisli ; Till Opatz
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：May 20, 2016
• 年：2016
• 卷：81
• 期：10
• 页码：4112-4121
• 全文大小：460K
• 年卷期：0
• ISSN：1520-6904

文摘

Various heterocyclic structures containing the pyrrole moiety have been synthesized from easily accessible 3,4-dihydro-2H-pyrrole-2-carbonitriles in one-pot procedures. 5,6,7,8-Tetrahydroindolizines, 2,3-dihydro-1H-pyrrolizines as well as 6,7,8,9-tetrahydro-5H-pyrrolo[1,2-a]azepines were obtained from these precursors in high yields in an alkylation/annulation sequence. The same conditions were applied in the synthesis of a 5,8-dihydroindolizine, which could easily be transformed to the corresponding indolizine by dehydrogenation. Furthermore, oxidative couplings of 3,4-dihydro-2H-pyrrole-2-carbonitriles with copper(II)-salts furnished 2,2′-bipyrroles as well as 5,5′-bis(5-cyano-1-pyrrolines), depending on the reaction conditions. Overall, these methods give high yielding access to a variety of pyrrole-containing heterocyles in two steps from commercially available starting materials.