摘要:
The tungsten complex W(CO)5[PPh2(CS2C3H3)] (2) undergoes dimerization, giving W2(CO)10[P2Ph4(C8H6S4)] (3). Protonation of 2 produces the intramolecular cyclization product W(CO)5[PPh2(CS2C3H4)]BF4 (4), and protonation Of W(CO)5[PPh2(CS2CH2C=N)] (7) also gives W(CO)5[PPh2(CS2C2NH3)]BF4 (8), which is converted back to 7 by BuLi. The structures of 3 and 8 are determined by X-ray diffraction. Deuterium labeling studies along with the solvent effect clearly indicate that the dimerization involves an unprecedented S-assisted intermolecular cycloaddition of the propargyl and thiocarbonyl groups of 2, forming a heterocyclic five-membered thiolene ring.