An improved catalyst for ring-closing alkyne metathesis based on molybdenum hexacarbonyl/2-fluorophenol

[GRAPHICS] An improved instant catalyst for ring-closing alkyne metathesis reaction is described. Catalyst formed in situ from molybdenum hexacarbonyl and 2-fluorophenol can be used without exclusion of air and moisture and shows high activity in metathesis of functionalized diynes. This system allows cyclization of substrates which were incompatible with previously known Mo(CO)(6)/phenol catalysts.