Oxidative Three-Component Carboamination of Vinylarenes with Alkylboronic Acids

The three-component carboamination of alkenes is of significant interest due to the ease by which functionalized amines can be produced from readily available chemical building blocks. Previously, a variety of carbon-centered radical precursors have been studied as the carbon components for this reaction; however, the use of general alkyl sources has remained as an unsolved challenge. Herein we present our efforts to develop an oxidative carboamination protocol that utilizes alkylboronic acids as carbon-centered radical precursors. The presented work demonstrates 34 examples, ranging from 17 to 88% yields, with a broad scope in vinylarenes, amines, and alkylboronic acids. Preliminary mechanistic studies suggest that a single-electron oxidation of the alkylboronic acid generates a carbon-centered radical intermediate that adds across the olefin followed by C-N bond formation via Cu-mediated inner-sphere or carbocation-mediated pathways.

Automated summary

This study developed an oxidative carboamination protocol utilizing alkylboronic acids as carbon-centered radical precursors to efficiently produce a variety of functionalized amines, with a broad scope in vinylarenes, amines, and alkylboronic acids. Preliminary mechanistic studies revealed a single-electron oxidation of the alkylboronic acid to generate a carbon-centered radical intermediate that undergoes C-N bond formation across the olefin.