A general ligand design for gold catalysis allowing ligand-directed anti-nucleophilic attack of alkynes.
Most homogenous gold catalyses demand ≥ 0.5 mol% catalyst loading. Owing to the high cost of gold, these reactions are unlikely to be applicable in medium- or large-scale applications. Here we disclose a novel ligand design based on the privileged (1,1'-biphenyl)-2-ylphosphine framework that offers a potentially general approach to dramatically lowering catalyst loading. In this design, an amide group at the 3'-position of the ligand framework directs and promotes nucleophilic attack at the ligand gold complex-activated alkyne, which is unprecedented in homogenous gold catalysis considering the spatial challenge of using ligand to reach anti-approaching nucleophile in a linear P-Au-alkyne centroid structure. With such a ligand, the gold(I) complex becomes highly efficient in catalysing acid addition to alkynes, with a turnover number up to 99,000. Density functional theory calculations support the role of the amide moiety in directing the attack of carboxylic acid via hydrogen bonding.
Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
Yanzhao
Y
Wang
Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
Zhixun
Z
Wang
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Ling Ling Road 345, Shanghai 200032, China.
Yuxue
Y
Li
Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
Gongde
G
Wu
Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
Zheng
Z
Cao
Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
Liming
L
Zhang
D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D006046:Gold / Q000737:chemistry*; D013237:Stereoisomerism
D000480:Alkynes; D006046:Gold