Selective Hydrofunctionalization of N-Allenyl Derivatives with Heteronucleophiles Catalyzed by Brønsted Acids

Abstract

In this study, we present a novel and environmentally sustainable protocol for the γ-hydrofunctionalization of N-allenyl compounds using various heteronucleophiles catalyzed solely by simple Brønsted acids. The method displays remarkable attributes, highlighting its sustainability, efficiency, regio-and stereoselectivity, as well as its versatile applicability to diverse heteroatom-containing enamides. Notably, our approach eliminates the need for metal catalysts and toxic solvents, representing a significant advancement in greener chemistry practices. We demonstrate the broad scope of our protocol by successfully scaling up reactions to gram-scale syntheses, underscoring its robustness for potential industrial implementation. The resulting γheterosubstituted enamides offer new possibilities for further synthetic transformations, yielding highly functionalized compounds with diverse applications. Mechanistic investigations reveal the pivotal role of CSA as a catalyst, enabling alcohol addition via a covalent activation mode.