Ficini Reaction with Acrylates for the Stereoselective Synthesis of Aminocyclobutanes.

The first Ficini reaction between ynamides and acrylates is reported herein. The reaction is catalyzed by B(CF) acting as a Lewis acid and is giving access to stable tri-substituted aminocyclobutenes in high yield. The resulting products can be hydrogenated and epimerized under basic conditions or in presence of a Lewis acid, providing two distinct trans- aminocyclobutane monoester stereoisomers in high yield and diastereoisomeric ratio (up to quantitative yield and >99 : 1 dr).