Isolation of highly nucleophilic gold(I) alkoxides having a tertiary phosphine ligand

Abstract

Alkoxogold(i) complexes having a tertiary phosphine ligand,Au(OR)L [R = CH2CF3, CH(CF3)2; L = PPh3, PCy3] have been synthesized by the metathetical reactions of chloro(tertiary phosphine)gold(i) and potassium fluorinated alkoxides in tetrahydrofuran at room temperature.

Coordination Chemistry of Gold Catalysts in Solution: A Detailed NMR Study

“…From general Equations (46)-(48) in Scheme 4 it becomes clear that the quantity of hydroxide ions per mole of gold increases for the following syntheses: (LAu) 2 OH + < (LAu) 3 O + < LAuOH. Hence, we concluded that the new species intermediately arising and disappearing on the way from (L2Au) 2 OH + (10) to L2AuOH (15) must be (L2Au) 3 O + (17). We automatically concluded that 10 and 15 react with each other to give (L2Au) 3 O + (17) according to Equation (45) in Scheme 4.…”

“…The exact chemical shift of the proton is slightly affected by the presence of water, which forms strong hydrogen bonds and causes exchange of the protons, so that no coupling to phosphorus is observable. [17] Indeed, in an extra-dry solution of 15 in C 6 D 6 (above solid KOH) the OH proton could be observed as a doublet at À0.20 ppm ( 3 J H-P = 4.8 Hz), and the doublet was also nicely observed in the NMR spectrum of 15 in C 6 D 6 layered above saturated aqueous KOH solution.…”

Gold(I) and gold(III) complexes with anionic oxygen donor ligands: hydroxo, oxo and alkoxo complexes

“…The sterically bulky Bu t OAuPPh3 (27) and the fluoroalkoxides ROAuPR'3 (R = CH(CF3)2, CH2CF3; R' = Ph, Cy) (28), which are readily prepared from the chlorides by simple metathetical reactions, are able to abstract hydrogen atoms from transition metal hydrides to give Au(I) heterodinuclear complexes, having Au-M bonds, with the liberation of the corresponding alcohols (38,39). Complexes 28 can abstract protons from various organic substances such as malononitrile, methylcyanoacetate and even acetone to give the corresponding organogold compounds and the free alcohol (40). By reaction with an equimolar amount of phenol in benzene they are converted into the phenoxogold(I) complexes, thus indicating the higher stability of the latter derivatives with respect to the alkoxides (40).…”

“…Complexes 28 can abstract protons from various organic substances such as malononitrile, methylcyanoacetate and even acetone to give the corresponding organogold compounds and the free alcohol (40). By reaction with an equimolar amount of phenol in benzene they are converted into the phenoxogold(I) complexes, thus indicating the higher stability of the latter derivatives with respect to the alkoxides (40). Catalytic amounts of complexes 28 are found to promote Knöevenagel condensation reactions between benzaldehyde and the active methylene compounds CH2(X)(Y) which are able to react with 28 as indicated in Equation 16 (7).…”

Recent Developments in the Chemistry of Fluorinated Isopropoxides and Tertiary Butoxides

“…Synthesis of air and thermally stable Au(I) and Au(HI) alkoxy complexes AuORpL and Me2AuORpL (L=PR3) is readily accomplished by metathesis between KORp and the corresponding halide in THF (equation 4) (21,22). The Au(I) complexes are found to be highly nucleophilic, abstracting protons smoothly from malonitrile, methylcyanoacetate and even acetone to form the corresponding C-bonded Au(I) enolate and HORp.…”