# Markovnikov hydroamination of terminal alkenes by phosphine redox catalysis

## TL;DR

A new catalytic system using phosphine and photoredox catalysts enables a chemical reaction that was previously only possible with transition metals.

## Contribution

The study introduces a novel main-group catalytic mechanism mimicking transition metal reactivity for alkene functionalization.

## Key findings

- A phosphine–photoredox system enables Markovnikov hydroamination of terminal alkenes with N–H azoles.
- The mechanism involves a phosphine radical cation activating alkenes for nucleophilic amination.
- This offers a new pathway for main-group catalysis in chemical synthesis.

## Abstract

Main-group catalysts that mimic transition metal reactivity can expand substrate tolerance and enable transformations not possible at present with metal catalysis1. The discovery that PIII and PV phosphorus intermediates can undergo transition-metal-like two-electron chemistry raises the question of whether radical PIV intermediates can mimic other elementary steps in organometallic chemistry2,3. Here we describe a phosphine–photoredox catalyst system that promotes intermolecular Markovnikov hydroamination of unactivated terminal alkenes with numerous classes of N–H azoles, a reaction that is not possible with late transition metal catalysis. Experimental and computational mechanistic studies support a new elementary step for main-group catalysis, in which a phosphine radical cation activates the alkene to nucleophilic amination by the azole, a step otherwise associated with transition metals. Given the broad value of nucleophilic alkene functionalization in transition metal catalysis, this PIV mechanism could offer new opportunities for main-group element catalysis and chemical synthesis.

A phosphine–photoredox catalyst system promotes intermolecular Markovnikov hydroamination of unactivated terminal alkenes with numerous classes of N–H azoles..