Metal catalysts have been used for several years in chemical industry for bulk manufacturing. However, the use of organometallic catalysts is still comparatively new and underdeveloped.
Research and development has resulted in modification of certain organometallic based processes in various industries. These catalysts and associated procedures are primarily used in pharmaceutical, agrochemical and fragrance production.
Topics in Organometallic Chemistry, a book series started by the renowned publisher, Springer, has a volume dedicated to organometallic catalysts and their use in fine chemical industry. It majorly focuses on palladium and ruthenium as two of the most commonly used catalysts.
Let’s review a few reactions catalyzed by these organometallic catalysts, in context with their industrial use.
§ Palladium catalyzed reactions
Palladium catalyzes C-C coupling reactions offering cost reduction benefits. The catalyst is tolerant to a number of functional groups, yielding no waste during the process. With palladium as a catalyst, these reactions require lower temperatures.
A wide range of reactions are carried out, mainly for the production of pharmaceutical intermediates. Without getting into detail of individual reactions, we’ll generally go over a few types of reactions.
Mirozoki-Heck reaction: It arylates an alkene, in some cases, arrylating allylic alcohols to finally produce a ketone or an aldehyde.
Suzuki reaction: It is used for production of biaryl compounds from arylboronic acid and aryl halide derivatives. This reaction is commonly used for manufacturing six different blood pressure lowering agents (sartans).
Kamada-Corriu reaction: Here an alkenyl or aryl Grignard is coupled with an alkenyl or aryl halide.
Negishi reaction: It couples an arylzinc with an alkenyl or aryl halide. While it is a highly selective reaction, zinc waste is a concern.
Sonogashira reaction: It couples a terminal alkenyl to an alkenyl or aryl halide.
These reactions often use metal-phosphine complexes for effective catalysis.
§ Ruthenium catalyzed reactions
Ruthenium mainly catalyzes selective hydrogenation reactions. These are adopted by the flavor and fragrance industry for production of unsaturated alcohols to be used as synthetic intermediates or final ingredients.
Ruthenium offers environmentally friendly reactions for selective 1,4-hydrogenation reactions of dienes. Ruthenium complexes are used for this purpose.
Asymmetric hydrogenation reactions of C=C, C=O and C=N are now being used in industrial pilot- or bench-scale reactions, catalyzed by ruthenium-, rhodium- or other metal complex catalysts.
Following three are routinely used phosphine ligands in most reactions.
- 2-diphenylphosphinobenzaldehyde: http://watson-int.com/2-diphenylphosphinobenzaldehyde-cas-50777-76-9-3/
- Xantphos: http://watson-int.com/xantphos-cas-161265-03-8/
- NiXanthphos: http://watson-int.com/nixanthphos-cas-261733-18-0/
Call now to order or contact us online.