Utilization of CS2 as a source of C1 synthetic units for the preparation of bis(alkylthio)methanes and alkyl dithioformates

Double insertion of CS2 into two Ru-H bonds of (dppm)2Ru(H)2] (dppm = Ph2PCH2PPh2) affords the methanedithiolate complex (dppm)2Ru(eta2-S2CH2)]. The methanedithiolate moiety has been functionalized using 2 equiv of RX resulting in bis(alkylthio)methane derivatives (dppm)2Ru(RSCH2SR)]X]2. The bis(alkylthio)methane complex loses the bis(alkylthio)methane moiety under very mild conditions and in turn affords the (dppm)2RuX2] complex from which the starting dihydride (dppm)2Ru(H)2] has been regenerated via reaction with KOH/EtOH. On the other hand, insertion of CS2 into one Ru-H bond of (dppe)2Ru(H)2] (dppe = Ph2PCH2CH2PPh2) followed by functionalization using RX results in alkyl dithioformate complex trans-(dppe)2Ru(H)(SC(SR)H)]X]. In this case also, the alkyl dithioformate moiety gets eliminated under very mild conditions to afford the (dppe)2Ru(H)(X)] derivative from which the starting dihydride has been regenerated via reaction with NaBH4. The reactions presented here constitute utilization of CS2 as a C1 synthetic source for the generation of useful organic compounds.