A Pathway for NH Addition to Styrene Promoted by Gold

Abstract

Going for gold! The synthesis of aziridines using heterogeneous gold catalysts has an unanticipated potential. Chemisorbed atomic oxygen is used to activate ammonia, producing NH bound to the gold surface (see scheme). Addition of NH across the double bond of styrene gave 2‐phenylaziridine on a single‐crystal Au(111) surface.

Highly Selective Acylation of Dimethylamine Mediated by Oxygen Atoms on Metallic Gold Surfaces

“…[8,[16][17][18][19][20] The general concept for amine acylation on O/Au(111) originates in the chemical nature of adsorbed oxygen and other nucleophilic adsorbates formed by selective deprotonation of their conjugate acids. For example, adsorbed O on Au surfaces activates alcohols, [17] ammonia, [19,20] and amines [8] through Brønsted acid-base reactions:…”

Reactions of small molecules on gold single crystal surfaces

“…Au(111) is often considered as a good model surface for understanding the details of heterogeneous Au-based oxidation catalysis on the molecular level [10]. Therefore, this surface has been much more studied than other surfaces, as will be seen in this paper.…”

“…Friend's group reported also on functionalization of an olefin with NH on Au(111), which may have advantages and mechanistic differences when compared to aziridination in solution or in other methods of activating ammonia for amination [10,54]. Aziridines are structurally analogous to epoxides and may be formed by addition of a nitrene group to the olefin.…”

“…Functionalization of styrene to form N-containing hydrocarbons, e.g. 2-phenylaziridine, benzonitrile, and benzyl nitrile, is achieved by reaction with adsorbed NH ads and N ads on Au(111) (Scheme 3) [10,54]. Electron-induced decomposition of condensed NH 3 was used to produce NH ads , N ads and H ads on Au(111) at 110 K. The addition of NH to styrene results in the production of 2-phenylaziridine, whereas adsorbed N and H atoms lead to the formation of nitriles benzonitrile and benzyl nitrile and, respectively, ethylbenzene.…”

Highly Selective Acylation of Dimethylamine Mediated by Oxygen Atoms on Metallic Gold Surfaces

“…Our approach is to investigate O-covered Au(111), since without oxygen, Au is inert towards many reactions, including those of alcohols, aldehydes, and amines. [8,[16][17][18][19][20] The general concept for amine acylation on O/Au(111) originates in the chemical nature of adsorbed oxygen and other nucleophilic adsorbates formed by selective deprotonation of their conjugate acids. For example, adsorbed O on Au surfaces activates alcohols, [17] ammonia, [19,20] and amines [8] through Brønsted acid-base reactions:These same O-covered Au surfaces are active for selfcoupling of alcohols and cross-coupling between methanol and aldehydes.…”