Synthesis and Structure of Cationic Phosphine Gold(I) Enol Ether Complexes

Abstract

Cationic {[(t-Bu) 2 (o-biphenyl)P]Au(enol ether)} + SbF 6 − and {[(t-Bu) 3 P]Au(enol ether)} + SbF 6 − complexes were isolated and characterized by NMR spectroscopy and X-ray crystallography. For three of the four complexes characterized in the solid state, gold coordinates to the electronrich bond in a η 1 fashion, while a 2,3-dihydrofuran complex displays η 2 coordination.

A Unique Au–Ag–Au Triangular Motif in a Trimetallic Halonium Dication: Silver Incorporation in a Gold(I) Catalyst

“…In our recent efforts to synthesize gold(I) enol ether complexes,7 we adopted a procedure of mixing phosphine gold(I) chlorides with AgSbF 6 in CH 2 Cl 2 followed by filtration through Celite. According to experimental procedures described in the literature, this was expected to coincide with an initial quantitative precipitation of solid AgCl and formation of R 3 PAu + SbF 6 − , which would remain in solution 13.…”

“…[4] Additionally, there is a growing trend toward the development of silver-free catalysts, due to the ambiguity of silver involvement and stoichiometry. [5,6] In our efforts to prepare mechanistically relevant gold complexes [7] from the preparative combination of phosphine gold chlorides and silver salts, we have encountered situations where the expectation of "quantitative precipitation of AgCl" [10a] was inconsistent with our observations. We thus sought to more carefully explore the solution chemistry of silver/gold mixtures.…”

Unexpected Anion Effect in the Alkoxylation of Alkynes Catalyzed by N‐Heterocyclic Carbene (NHC) Cationic Gold Complexes

“…The same asymmetry has been experimentally observed, too. [33] Finally, the vinyl ether can de-coordinate and be substituted by another molecule of alkyne. [34] From the structure of TS_attack, the experimentally observed anion effect (Figure 1) can be rationalized on the basis of the coordinating and basicity properties of the different anions.…”

Mechanistic insights and functionalization of alkynes in homogeneous gold catalysis.

“…As expected, hydrogen bond acceptors with lower gold affinity (e.g., DMPU, DMF) [141][142][143][144][145][146][147][148] enhanced the rate of reaction (Scheme 14b), and ionic hydrogen bond acceptors (e.g., Bu4N Other research groups reported that certain compounds improved the chemical yields in selected gold catalyzed reactions. 153,154 One notable example is the …”