Base‐Induced Decarboxylation of Polyunsaturated α‐Cyano Acids Derived from Malonic Acid: Synthesis of Sesquiterpene Nitriles and Aldehydes with β‐, φ‐, and ψ‐End Groups |
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Authors: | Laurent Dufossé Dominique Cartier Benoist Valla Mireille Fouillaud Roger Labia Alain Valla |
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Institution: | 1. Laboratoire de Chimie des Substances Naturelles et des Sciences des Aliments, Université de La Réunion, ESIROI‐IDAI, 2 rue Joseph Wetzell, F‐97490 Sainte‐Clotilde, La Réunion;2. Chimie et Biologie des Substances Naturelles, CNRS FRE 2125, 6 rue de l'Université, F‐29000 Quimper |
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Abstract: | Catalytic base‐induced decarboxylation of polyunsaturated α‐cyano‐β‐methyl acids derived from malonic acid led to the corresponding nitriles 3 (Schemes 2 and 3), 6 (Scheme 5), and 9 (Scheme 6). This decarboxylation occurred with previous deconjugation of the α,β‐alkene moiety of the α‐cyano‐β‐methyl acid, leading to an α‐cyano‐β‐methylene propanoic acid which was easily decarboxylated (see Scheme 2). β‐Methylene intermediates, in some cases, could be isolated; mechanistic pathways are proposed. The nitriles 3, 6 , and 9 were reduced to the sesquiterpene aldehydes 4 (β‐end group), 7 (φ‐end group), and 10 (ψ‐end group), respectively. |
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Keywords: | Sesquiterpenes Polyunsaturated α ‐cyano‐β ‐methyl acids Malonic acid Decarboxylation |
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