PREPARATION OF CYCLIC AND ACYCLIC THIOETHERS VIA HEXACARBONYLDICOBALTALKYNE COMPLEXES

Demetallation of [Co2{mu-C2(CH2SCH2CH2)2S}(CO)6] with trimethylamine N -oxide affords 1,4,7-trithiacycloundec-9-yne, while similar treatment of [Co2(CO)6{mu-(CCH2SCH2CH2SCH2CH2SCH2C)2}Co2(Co)6] affords 1,4,7,12, 15,18-hexathiacyclodocos-9,2-diyne. 20-diyne. A single crystal X-ray d iffraction study and H-1 NMR spectroscopy have confirmed that 1,4,7-tr ithiacycloundec-9-yne adopts an exodentate conformation in the solid a nd solution states. Trimethylamine N-oxide promoted Pauson-Khand react ions of [Co2(mu-R1C = CCH2SR2)(CO)6] (R1 = H, R2 = Et; R1 = Me, R2 = E t) or [Co2(mu-RSCH2=CCH2SR)(CO)6] (R = Et; R-R = CH2CH2, CH2CH2CH2 or CH2CH2SCH2CH2) with norbornene or of [Co2(mu-R1C=CCH2SR2)(CO)6] (R1 = H, R2 = Et; R1 = Me, R2 = Et) with norbornadiene afford a range of cyc lopentenone products, which have been characterised by NMR, IR and mas s spectroscopy.