Methanesulfonic Acid Mediated Cyclization and Meyer–Schuster Rearrangement of γ‐Amino‐ynones: Access to Enantiopure Pyrrolidine Exocyclic Vinylogous Amides. Issue 21 (12th June 2014)

• Record Type: Journal Article
• Authors: Vu, Huy‐Dinh; Renault, Jacques; Roisnel, Thierry; Gouault, Nicolas; Uriac, Philippe
• Is Part Of: European journal of organic chemistry. Issue 21(2014)
• Page Start: 4506
• Page End: 4514
• Publication Date: 2014-06-12
• Subjects: Rearrangement -- Nitrogen het­erocycles -- Alkynes -- Amines -- Cyclization -- Regioselectivity; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201402336
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: α‐ and β‐Amino‐ynones have been largely used to prepare heterocyclic rings in the presence of various electrophiles such as protic acids or gold(I). Herein we disclose the unprecedented formation of pyrrolidine exocyclic vinylogous amides, in place of the expected azepinones or piperidinones, starting from γ‐amino‐ynones derived from amino acids. The process involves a tandem 1, 2‐addition of the protected nitrogen to the carbonyl group followed by a Meyer–Schuster rearrangement, which efficiently afforded enantiopure pyrrolidine exocyclic vinylogous amides. The sequence is poorly catalyzed by gold salts, but proved to be very efficient in the presence of methanesulfonic acid. Abstract : Starting from γ‐amino‐ynones, the 1, 2‐addition of the protected nitrogen to the carbonyl group followed by a Meyer–Schuster rearrangement leads to pyrrolidine exocyclic vinylogous amides. This tandem reaction proved to be very efficient in the presence of methanesulfonic acid, leading to various enantiopure products.