Base-Mediated Generation of Ketenimines from Ynamides: [3+2] Annulation with Azaallyl Anions
Résumé
Under basic conditions and heat, ynamides can serve as precursor to ketenimines, whose synthetic potential is often hampered by their difficulty of access. Herein, we report that they can undergo a [3+2] cycloaddition with 2azaallyl 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 nitrogenrich heterocycles. The reaction usually proceeds with excellent diastereoselectivity, in favor of the cis adduct. Deuteration experiments and DFT calculations helped rationalize the regio-and stereo-selectivity of the process as well as the formation of side-products.
Domaines
Chimie organiqueOrigine | Fichiers produits par l'(les) auteur(s) |
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