UC Santa Barbara

Most ligands used in asymmetric gold(I) catalysis are directly adopted from palladium catalysis. These ligands were initially designed to facilitate the chemistry of square-planar Pd(II) complexes and hence are hardly optimal for Au(I) catalysis, in which the catalysts display linear geometry. For the past several years, the Zhang Lab has designed various bifunctional biphenyl-2-ylphosphine ligands featuring a remote basic group to harness the linear Au(I) structure and enable ligand-metal cooperation. During the research of this dissertation, a new type of bifunctional phosphine ligands possessing a chiral center and a fluxional biphenyl axis were developed to enable asymmetric isomerization of propargylic alcohols and sulfonamides into chiral 2,5-dihydrofurans and chiral 3-pyrrolines, respectively. The synthetic potential of this methodology was demonstrated in a total synthesis of diplobifuranylone B. Notably, this type of chiral ligands is also suitable for Ag(I) and Cu(I) catalysis. β, γ-Butenolides was isomerized into chiral α, β-butenolides with high enantiomeric excesses via enantioselective γ-protonation under Cu(I) catalysis.