1,2-Digold(I) alkenes: synergistic dimetalation synthesis and photoinduced C–Cl activation

Abstract

Di- and poly-metalation of organic molecules provides a powerful platform for constructing structurally diverse organometallic compounds and enabling multi-site functionalization. However, the mechanistic details of sequential metalation, especially the interplay between consecutive metalation steps, remain poorly understood. Here, we report a synergistic dimetalation strategy for the efficient synthesis of 1,2-digold(I) alkenes from alkenyl 1,2-bis(boronate) esters. In this process, the alkenyl monogold(I) intermediate readily captures a coordinatively unsaturated gold(I) species by aurophilic interactions to form a gem-digold(I) structure, which then undergoes a base-promoted 1,2-gold migration with elimination of the boronate group to afford the 1,2-digold(I) alkene in nearly quantitative yield. We proved the general applicability of this synergistic dimetalation approach by synthesizing a diverse set of 1,2-digold(I) alkenes. Upon photoexcitation, it efficiently activates the C–Cl bond of dichloromethane, generating chloromethyl radicals and causing the catalytically inactive mixed-valence gold(I)/gold(0) nanoclusters. By elucidating the aurophilic interaction-based synergistic dimetalation mechanism, this work not only provides a rational route to polymetalated organic molecules but also unveils a photoinduced pathway for C–Cl bond activation of solvent molecules, offering a new insight into the deactivation of gold(I) catalysts.