Selective Reduction of Secondary Amides to Imines Catalysed by Schwartz's Reagent.

Autor: Donnelly LJ; Université Paris-Saclay, CEA, CNRS, NIMBE, 91191, Gif-sur-Yvette, France., Berthet JC; Université Paris-Saclay, CEA, CNRS, NIMBE, 91191, Gif-sur-Yvette, France., Cantat T; Université Paris-Saclay, CEA, CNRS, NIMBE, 91191, Gif-sur-Yvette, France.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2022 Aug 15; Vol. 61 (33), pp. e202206170. Date of Electronic Publication: 2022 Jun 14.
DOI: 10.1002/anie.202206170
Abstrakt: The partial reduction of amides is a challenging transformation that must overcome the intrinsic stability of the amide bond and exhibit high chemoselective control to avoid overreduction to amine products. To address this challenge, we describe a zirconium-catalysed synthesis of imines by the reductive deoxygenation of secondary amides. This reaction exploits the excellent chemoselectivity of Schwartz's reagent (Cp 2 Zr(H)Cl) and utilises (EtO) 3 SiH as a mild stoichiometric reductant to enable catalyst turnover. The reaction generally proceeds with high yields (19 examples, 51 to 95 % yield) and tolerates a variety of functional groups (alkene, ester, nitro, etc.). Stoichiometric mechanistic investigations suggest the regeneration of the active [Zr]-H catalyst is achieved through the metathesis of Si-H and Zr-OR σ-bonds.
(© 2022 Wiley-VCH GmbH.)
Databáze: MEDLINE
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