An attractive strategy for generation of α-amino anions from aldehydes with applications in synthesis of homoallylic amines is described. Aromatic aldehydes can be converted to α-amino anion equivalents via amination with 2,2-diphenylglycine and subsequent decarboxylation. The in situ generated α-imino anions are highly reactive for Pd-catalyzed allylation, forming the corresponding homoallylic amines in high yields with excellent regioselectivity.

Thioamides are unique and versatile synthetic building blocks with S, N, and α-C three adjacent nucleophile centers, however, they are rarely used as carbon nucleophiles for transition-metal-catalyzed C–C coupling reactions. This Letter describes the first Pd-catalyzed α-arylation of thioamides and demonstrated the feasibility of the application of thioamides in coupling chemistry. By the coupling process, a variety of α-arylated thioamides were prepared in moderate to good yields under mild reaction conditions, which provides an alternative way to access functionalized thioamides as well as a new synthetic transformation for thioamides. High chemoselectivity for thioamide over amide was observed in the reaction.

This work describes the first Pd-catalyzed allylic alkylation of thioamides. Various thioamides were efficiently α-allylated in high yields and with excellent selectivity for monoallylation under mild reaction conditions. The process not only provides a facile method for the synthesis of functionalized thioamides, but also presents a useful transformation for synthetically important thioamides.Figure optionsDownload full-size imageDownload as PowerPoint slide