A Gold(I) Complex with a 1,1′-Binaphthyl-Substituted Diphosphene: Synthesis, Structure, and Catalytic Application to Intramolecular Hydroarylation Reactions

A gold(I) complex with a 1,1′-binaphthyl-substituted diphosphene was synthesized and fully characterized. A phosphorus atom with a less-hindered binaphthyl group coordinates to a gold(I) moiety in an η1 fashion. Both experiment and theoretical calculations supported the facile rotation around the C(Naph)–P bond in neutral and cationic diphosphene–gold(I) complexes. The newly obtained complex 2 was applied to the intramolecular hydroarylation of aryl propynyl ethers 5, and 2H-chromenes 6 were formed in 83–94% yield. Furthermore, the chiral diphosphene–gold(I) complex (S)-2 was used in the atropselective reaction to furnish 6b,c with up to 9% ee, which is the first example of the use of a diphosphene as a ligand for the transition-metal-catalyzed organic transformation.