Poster De Conférence Année : 2023

Evaluation of transition metal tridentate pincers for the preparation of N-metallated nitriles

Résumé

In the United States, in 2011, among the top 200 drugs sold, 21 have at least one quaternary center derived from a natural product and none of these stereocenters have been created by chemical synthesis. It should be noted that the construction of two adjacent stereocenters is a major issue in organic synthesis. Therefore, the development of new strategies based on catalytic methods for the synthesis of enantiopure molecules with contiguous "all carbon" centers remains a very active area of research. In this context, α-cyanocarbanions have emerged as valuable intermediates due to their excellent reactivity as nucleophiles and the possible transformation of the nitrile group into a wide variety of other functions. In this field, methodologies based on N-silylated (SKI) or N-metalated (N-MKI) ketene imines have attracted particular attention as potent α-cyano carbanion equivalents, as they offer unique synthetic opportunities in asymmetric catalysis. Regarding the enantioselective elaboration of vicinal stereocenters, significant works have been published on the application of N-silyl ketene imines (SKIs) in aldol and Mannich reactions. However, these reactions possess a limited field of application due to the need for a strong base in stoichiometric amounts to generate the SKI species. On the contrary, N-metallated ketene imines can be easily formed in the presence of a mild base thanks to the coordination of the nitrile to the metallic center. However, such intermediate species remain scarcely reported. Nakamura and very recently Shibasaki have postulated their existence in asymmetric Mannich-type reactions catalyzed by, respectively, a NCN-Pd Pincer (Phebim-type) and a CCC-Ni pincer (bis-triazolylidene-type). Regarding the actual problematic associated with endangered noble metal such as Pd, we propose to widen the scope of more abundant and less expensive Ni derivatives by using tridentate NNN-Ni pincers in alpha-cyanoalkylation reactions involving imines or aldehydes.

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Dates et versions

hal-05423645 , version 1 (18-12-2025)

Identifiants

  • HAL Id : hal-05423645 , version 1

Citer

Mamoudou Doucoure, Janick Ardisson, Marie-Isabelle Lannou. Evaluation of transition metal tridentate pincers for the preparation of N-metallated nitriles. 26ème Journée de Chimie Organique et Chimie Organique Biologique de la Montagne-Ste-Geneviève, Jun 2023, Paris, France. ⟨hal-05423645⟩
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