Ring-closing alkyne metathesis tungsten alkylidyne complex

At the same time, Filrstner used tungsten alkyUdene complex 150 developed by Schrock for ring-closing alkyne metathesis. He compared the reactivities of tungsten alkylidyne complex 150 and Mo(CO)6-p-ClC6H40H (Table 6.4) and showed that both catalysts work well, although a higher reaction temperature is required in the case of Mo(CO)6-p-chlorophenol. 

At the same time, Fiirstner and others used Schrock s tungsten alkylidyne complex 120 for ring-closing alkyne metathesis. They compared 120 with the Mo(CO)6-/>-ClC6H40H system (Table 4) in reactivity and found that... 

Ring-closing metathesis (RCM) is not restricted to alkenes similar reactions are also known for alkynes. The tungsten alkylidyne complex W(=CCMe3)(OCMc3)3 has been used to catalyze such reactions. Predict the structures of the cyclic products for metathesis of... 

J., Hrib, C.G., Jones, P.G., and Tamm, M. (2008) Preparation of cyclophanes by room-temperature ring-closing alkyne metathesis with imidazolin-2-iminato tungsten alkylidyne complexes. Org. 

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