Chemo-selective Stille-type coupling of acyl-chlorides upon phosphine-borane Au(i) catalysis

Phosphine-boranes do not promote oxidative addition of acyl chlorides to gold, but the phosphine-borane gold triflimide complex [i Pr2P(o-C6H4)BCy2]AuNTf2 was found to catalyze the coupling of acyl chlorides and aryl stannanes. The reaction involves aryl/chloride-bridged dinuclear gold(I) complexes as key intermediates, as substantiated by spectroscopic and crystallographic analyses. Similar to Pd(0)/Pd(II)- catalyzed Stille coupling with phosphine-borane ligands, the gold-catalyzed variant shows complete chemoselectivity for acyl chlorides over aryl iodides and bromides, enabling straightforward access to halogenated aryl ketones.