- Reagent Availability
- Experimental User Friendliness
The palladium catalyst supported on calcium carbonate and partially deactivated (“poisoned”) with lead acetate and quinoline is called the Lindlar catalyst.
Using the Lindlar catalyst, the hydrogenation of alkynes stops at alkenes without further hydrogenation to alkanes. This chemoselectivity is explained by the stronger adsorption of alkynes to the catalyst surface than alkenes. The hydrogenation is also stereoselective and Z-alkenes are produced as a major product.
・Lindlar, H. Helv. Chim. Acta 1952, 35, 446. doi:10.1002/hlca.19520350205
The synthesis of manzamine A.
The chemoselectivity is sensitive to various factors and not always perfect. One needs to monitor the reaction carefully.