Dimethylcuprate-Mediated Transformation of Acetate to Dithioacetate

Abstract

Dithiocarboxylic acids, RCS2H, and their esters, RCS2R′, are useful reagents that can be synthesized by the reaction of carbon disulfide with organometallic reagents. Here the coinage-metal-mediated transformation of acetate to dithioacetate is explored in the gas phase using multistage mass spectrometry experiments in a linear ion trap mass spectrometer in conjunction with density functional theory (DFT) calculations. The ion–molecule reactions between coinage-metal dimethylmetalate anions [CH3MCH3]− (M = Au, Ag, Cu), formed via double decarboxylation of the metal acetate anions, [CH3CO2MO2CCH3]−, and carbon disulfide, were examined. Only [CH3CuCH3]− reacts with CS2 with a reaction efficiency of 0.8% of the collision rate to yield the adduct [CH3CuS2CCH3]− (77.5%) as well as CH3CS2– (22.5%). Collision-induced dissociation (CID) of the adduct [CH3CuS2CCH3]− gives CH3CS2– as the major product, with a small amount of [CuS2CCH2]− being formed via loss of methane. DFT calculations reveal the following. (i) [C...