Organocatalysis with Chiral Formamides: Asymmetric Allylation and Reduction of Imines

Christine Baudequin (1) , Devdutt Chaturvedi (2) , Svetlana Tsogoeva (2, 3)

1 COBRA - Chimie Organique et Bioorganique : Réactivité et Analyse
2 Georg-August-University = Georg-August-Universität Göttingen
3 FAU - Friedrich-Alexander Universität Erlangen-Nürnberg = University of Erlangen-Nuremberg

Simple aldimine, derived from p‐nitrobenzaldehyde and 2‐aminophenol, reacts with allyltrichlorosilane in the presence of chiral N‐formylproline activator 5 and an L‐proline additive to afford the corresponding homoallylic amine in good yield (84 %) and with moderate enantioselectivity (43 % ee). The role of the second formamide moiety in the activator is crucial to bring about the enhancement in the reaction rate and enantioselectivity, as C2‐chiral bisformamide 1 promotes for the same allylation reaction in higher yield (94 %) and enantioselectivity (83 % ee). Chiral monoformamide 5 (10 mol‐%), with the assistance of HMPA as an additive, also catalyses the asymmetric reduction of ketimine 13 in the presence of trichlorosilane in good yield and enantioselectivity (75 %, 81 % ee).

Mots clés: chirality; formamides; organocatalysis; allylation

Domaines: Chimie organique; Catalyse

Christine Baudequin, Devdutt Chaturvedi, Svetlana Tsogoeva. Organocatalysis with Chiral Formamides: Asymmetric Allylation and Reduction of Imines. European Journal of Organic Chemistry, 2007, 2007 (16), pp.2623-2629. ⟨10.1002/ejoc.200700058⟩. ⟨hal-02385359⟩