Ligand-Regulated Palladium-Catalyzed Regiodivergent Hydroarylation of the Distal Double Bond of Allenamides with Aryl Boronic Acid

Pd(II)-catalyzed regioselective hydroarylation of allenyl-containing α-amino acid derivatives with aryl boronic acids

A convenient pathway to a new family of α,α-disubstituted α-amino acid derivatives bearing an aryl alkene moiety at the side chain has been developed. This method is based on hydroarylation of functional allenes with aryl boronic acids under Pd(II)/dppf catalysis. The studied reactions represent the first example of the metal-catalyzed arylation of allenyl-containing α-amino acid derivatives and allow for the efficient assembly of biologically valuable molecules under mild conditions in good yields and high regio- and stereoselectivity.

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

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 γ-heterosubstituted 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.

Palladium-catalyzed cascade cyclization of allenamide with 2-iodoanilines to access functionalized indoloquinolines

A novel and efficient palladium-catalyzed cascade cyclization to indoloquinoline derivatives in one pot has been developed by using allenamide derivatives and 2-iodoanilines as the key building blocks. The process involved two cyclizations: intramolecular cyclization/π-allylic substitution and intramolecular 6-endo Heck cyclization. Furthermore, dihydrobenzofuro[2,3-b]quinoline derivatives could also be achieved via this strategy using allenyl ethers instead of allenamides. The readily available substrates, mild conditions, high efficiency and step economy make this strategy a promising method in the synthesis of polycyclic motifs.

Palladium-catalyzed regiodivergent arylamination/aryloxygenation of allenamide

In regiodivergent arylamination/aryloxygenation of allenamides, use of Cy2NMe caused 2,1-arylamination and the corresponding alkenes were formed with excellent Z configuration. Whereas, utilizing Ag2CO3 caused 2,3-aryloxygenation via an unexpected CO2 insertion from Ag2CO3.