Markovnikov at Gold: Nucleophilic Addition to Alkenes at Au(III)

Abstract

The reactivity of Au(OAcF)2(tpy) (1, OAcF = OCOCF3; tpy = 2-(p-tolyl)pyridine) toward a wide variety of different alkenes with various substitution patterns and different oxygen-based nucleophiles has been investigated. These reactions are two-step processes where a ligand substitution is followed by a nucleophilic addition furnishing Au(III) complexes with C(sp3) ligands. In this work we have found that the reactions always occur trans to tpy-N while the OAcF ligand remains in place trans to tpy-C. The nucleophilic addition takes place exclusively at the most substituted side of the double bond, in a Markovnikov manner, and the nucleophilic addition occurs in an anti fashion as can be seen from the reaction with the 2,3-disubstituted alkene trans-2-hexene. This study has provided valuable insight into the scope and regiochemistry of Au(III) mediated nucleophilic additions, which is of great importance for further development of Au(III) catalysis and alkene functionalization.