Stepwise reduction of carbon disulfide in the coordination sphere of tungsten. A transition-metal-mediated synthesis of dithioacetals

Article abstract of DOI:10.1021/om50006a045

Reduction of mer-W(CO)₃(dppe)(η²-CS₂) (1) with LiHBEt₃ yields the dithioformate complex fac-Et₄N-[W(CO)₃(dppe)(η¹-SCHS)] (2) which may also be obtained by a simple ligand exchange reaction. Compound 2 reacts with alkyl halides in two steps via dithio ester complexes mer-W(CO)₃(dppe)(η²-SCHSR) (3) to dithiocarbenium ion derivatives mer-[W(CO)₃(dppe)(η²-R′SCHSR)]X (4). LiHBEt₃ reduces 4 to dithioacetal complexes mer-W(CO)₃(dppe)(η¹-R′SCH₂SR) (5) which isomerize photochemically to the corresponding fac compounds 6. Lewis bases readily displace the dithioacetal from 6 but not from 5.