Base-Mediated Generation of Ketenimines from Ynamides: [3+2] Annulation with Azaallyl Anions

Agathe D’hollander (1) , Eugénie Romero (1) , Kamsana Vijayakumar (1) , Camille Le Houérou (1) , Pascal Retailleau (1) , Robert H Dodd (1) , Bogdan Iorga (1) , Kevin Cariou (1)

1 ICSN - Institut de Chimie des Substances Naturelles

Under basic conditions and heat, ynamides can serve as precursor to ketenimines, whose synthetic potential is often hampered by their difficulty of acces. Herein, we report that they can undergo a [3+2] cycloaddition with 2-azaallyl anions, obtained from benzylimines under the same reaction conditions. This reaction between two highly reactive intermediates, both generated in situ from bench stable starting materials, gives access to various nitrogen-rich heterocycles. The reaction usually proceeds with excellent diastereoselectivity, in favor of the cis adduct. Deuteration experiments and DFT calculation helped rationalize the regio and stereo-selectivity of the process as well as the formation of side-products.

Domaines: Chimie organique

Agathe D’hollander, Eugénie Romero, Kamsana Vijayakumar, Camille Le Houérou, Pascal Retailleau, et al.. Base-Mediated Generation of Ketenimines from Ynamides: [3+2] Annulation with Azaallyl Anions. 2020. ⟨hal-02998846⟩