Mn2(CO)10-catalyzed direct protic hydrogen transfer with unactivated alkenes

Abstract

Transition-metal-catalyzed hydrogen-atom-transfer (HAT) reactions have proven to be effective strategies for obtaining important heterocycle scaffolds found in natural products. However, the electronic mismatch between metal catalysts and the protic hydrogen atom necessitates the use of excess oxidants and external reductive hydrogen sources in existing methods, which limit their practicality. To address this issue, we present a practical and efficient methodology for Mn₂(CO)₁₀-catalyzed intramolecular transfer of the protic hydrogen atom. A catalytic amount of tBuOOH is utilized promoting the HAT process, going beyond mere oxidation, thereby obviating the need for excess oxidants and external reductive hydrogen sources during the HAT process. Additionally, the dimeric manganese catalysis enables efficient dioxygenation, oxy-amination, oxy-sulfuration, and oxy-halogenation of alkenes. Comprehensive mechanistic studies have been done and suggest that a radical reaction pathway is involved in the proton transfer. This finding provides novel insights into the direct metal-catalyzed protic hydrogen atom-transfer reactions.