Terminal alkyne metathesis: A further step towards selectivity

Terminal alkyne metathesis has been improved by addition of quinuclidine as an external ligand to the (t-BuO)(3) W equivalent to CBu-t carbyne complex, giving a yield of 80% during hept-1-yne metathesis. Extension of this system to the co-metathesis of terminal and disubstituted alkynes affords the expected cross-reaction products.