Anti-Markovnikov Regioselective Hydroamination of Alkenes with Aqueous NH₃on a Au/TiO₂Photocatalyst

Key words

hydroamination - alkenes - gold catalysis - titanium oxide - photocatalysis - regioselectivity

Significance

A gold-loaded titanium oxide photocatalyst (Au/TiO₂), prepared according to Equation 1, promoted the hydroamination of alkenes with aqueous ammonia under xenon-lamp irradiation (λ ≥ 300 nm) to afford the corresponding amines in ≤96% yield with >99% anti-Markovnikov regioselectivity (eq. 2; 9 examples).

Comment

The authors have previously reported the preparation of the Pt/TiO₂ photocatalyst, and its application to the aromatic ring amination of benzenes with aqueous ammonia (J. Phys. Chem. C 2013, 117, 11047) and the anti-Markovnikov hydration of alkenes (Catal. Sci. Technol. 2013, 3, 1739). They propose that the thermodynamic stability of the radical intermediate generated from alkene and amide radical determine the anti-Markovnikov regio­selectivity (eq. 3). In the hydroamination of 4-phenylbut-1-ene, the catalytic activity of Au/TiO₂ was superior to that of Pt/TiO₂ or Pd/TiO₂.

Publication History

Article published online:
17 September 2020