Azide-Enolate Cycloaddition-Rearrangement Enables Direct α-Amination of Amides and Enelactam Synthesis from Esters.

Invited for the cover of this issue are Dan Furkert, Joe Bell-Tyrer and co-workers at the University of Auckland and Victoria University of Wellington. The image depicts a tandem cycloaddition-rearrangement process delivering a diverse range of molecular frameworks from simple precursors. Read the full text of the article at 10.1002/chem.202300261.

Azide-Enolate Cycloaddition-Rearrangement Enables Direct α-Amination of Amides and Enelactam Synthesis from Esters.

Azide-enolate cycloaddition-rearrangements offer potential for rapid access to diverse molecular frameworks from simple precursors. We report here that investigations into the cycloadditions of ester or amide enolates with vinyl azides led to the identification of two reaction processes - direct α-amination of amides and lactams, and the synthesis of ene-γ-lactams from esters. The outcomes of these reactions depended on the fate of key vinyl triazoline intermediates generated in the initial cycloaddition step. Isolation of reaction intermediates in the ene-γ-lactam synthesis revealed the unexpected addition of two enolate equivalents, one of which is later eliminated. Computational studies further suggested an unusual reaction pathway involving direct addition of an enolate to the terminal carbon of the N-vinyl triazoline. In contrast, the α-amination of amides and lactams proceeded by rearrangement of the intermediate triazoline to give an imine, hydrolysis or reduction of which gave access to primary or secondary α-amino amides or lactams.