Dinuclear Gold(I) “A-Frame” Complexes from Geminal Diauration of 2,4-Diketones, Methylenedisulfones, and Cyanomethyl Sulfones

Treatment of the disulfones RSO2CH2SO2R (R = Me, Ph) with 1 or 2 equiv of organolithium
reagents, followed by metathesis with a (phosphine/arsine)gold(I) halide, afforded high yields
of mono- or diaurated sulfones of the types [(R‘3P)Au]CH(SO2R)2 (R = R‘ = Ph) and [(R‘3P/As)Au]2{μ-C(SO2R)2} (R = Me, R‘3P = Ph3P, Ph2MeP, Ph3As; R = Ph, R‘3P = PPh3, Ph2MeP). Using the same procedure, PhSO2CH2CN was transformed into [(Ph3P)Au]2{μ-C(CN)SO2Ph}. The products are stable to air and moisture and decompose at temperatures
well above 150 °C. The crystal structure analysis of the diaurated compounds reveals compact
A-frame core units in which the central carbon atom forms a CAu2 triangle with an
exceedingly small Au−C−Au angle and, consequently, a short aurophilic Au- - -Au contact.
The corresponding angles S−C−S (or SAuC(N)) are widened in an overall distorted-tetrahedral environment. Attempted triauration using [(R‘3P)Au]+BF4- reagents was unsuccessful with the disulfones but gave the adduct {[(Ph3P)Au]2C(SO2Ph)CN[Au(PPh3)]}+BF4-,
in which the third gold atom is attached to the nitrile nitrogen atom. Benzyl phenyl sulfone
was monoaurated to give the chiral product [(Ph3P)Au]CH(Ph)SO2Ph. 3-[(Triphenylphosphine)gold]pentane-2,4-dione was found to undergo a redistribution reaction induced by tri-tert-butoxyaluminum in benzene solution to give the diaurated diketone [(Ph3P)Au]2{μ-C{C(O)Me}2]. Its crystal structure shows a core unit with bonding characteristics similar to
those of keto instead of sulfone/cyano substituents.