Harnessing the Electrophilicity of Keteniminium Ions: A Simple and Straightforward Entry to Tetrahydropyridines and Piperidines from Ynamides. Issue 14 (2nd March 2016)

• Record Type: Journal Article
• Authors: Lecomte, Morgan; Evano, Gwilherm
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 14(2016)
• Page Start: 4547
• Page End: 4551
• Publication Date: 2016-03-02
• Subjects: cationic cyclizations -- hydride shift -- keteniminium ions -- piperidines -- ynamides; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201510729
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: An efficient, modular and straightforward entry to tetrahydropyridines and piperidines is reported. This reaction is based on a formal intramolecular hydroalkylation of readily available, properly substituted ynamides which, upon simple activation under acidic conditions, generate highly reactive activated keteniminium ions whose reactivity can be finely controlled to induce a remarkably efficient [1, 5]‐hydride shift from unactivated C−H bonds and trigger a cationic cyclization which is complete within minutes. Abstract : Powerful electrophiles : properly substituted keteniminium ions, simply generated by acidic treatment of the corresponding ynamides, can induce a remarkably efficient [1, 5]‐hydride shift from unactivated C−H bonds. This triggers a cationic cyclization which gives, within minutes, highly functionalized tetrahydropyridine and piperidine derivatives.