A Simple Micellar Gold Catalyst Supported by a Hydrophilic Phosphinoferrocene Amidosulfonate Ligand

The design of micellar catalysts is instrumental in transferring metal‐catalyzed organic reactions into aqueous reaction media and enabling catalyst reuse. Herein, it is reported that phosphinoferrocene amidosulfonate Ph 2 PfcC(O)NHCH 2 SO 3 (HNEt 3 ) ( 1 , fc = ferrocene‐1,1′‐diyl) and its chlorogold(I) complex [AuCl( 1 ‐κ P )] ( 8 ) form stable micelles in water. The latter compound is found to be an efficient, self‐activating catalyst for the gold‐catalyzed cyclization of N ‐propargyl benzamide into 4,5‐dihydro‐5‐methylene‐2‐phenyloxazole in a water‐ethyl acetate mixture. Structure determination of 8 ·½CH 2 Cl 2 reveals extensive hydrogen bonding between the polar amidosulfonate pendants, in line with the compound's surfactant‐like behavior. Density functional theory calculations of the plausible LAu + type catalyst suggest a possible in situ self‐activation of complex 8 in water via chloride loss, possibly facilitated by the amidosulfonate group and the formation of Au(I)‐aqua species.