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The 2010 Nobel Prize In Chemistry: Palladium As Catalyst For Carbon Coupling

 

Palladium-catalysed cross coupling was used to synthesize a potent anti-cancer agent, discodermolide, produced by this sponge.: image via marinebiotech.orgPalladium-catalysed cross coupling was used to synthesize a potent anti-cancer agent, discodermolide, produced by this sponge.: image via marinebiotech.org

The 2010 Nobel Prize in Chemistry, its seminal work by Richard F. Heck  and its variations by Ei-ichi Negisi and Akira Suzuki,has been awarded for the discovery of palladium as a catalyst in forming carbon bonds.  This discovery has already impacted many areas of science, from medicine to agriculture to electronics. Like the 2010 Nobel Prize in Physics, awarded yesterday, the chemistry award acknowledges advancements in carbon enhancement.

What occurs in nature between simple carbon elements is very difficult to achieve in the laboratory.  For example, for the last two decades, scientists have tried to recreate the ability of Discodermia dissoluta, a marine sponge that can't see, hear, or move, yet protects itself from predators by emitting a powerful poison.  It has been found that the natural compound in the Discodermia dissoluta, discodermolide, is a powerful anti-cancer weapon; however, the Discodermia dissoluta sponge is rare and cannot possibly supply the amount of natural discodermolide necessary to create a wide-scale medicinal application from it.

The works of the three Nobel Prize winners today have been essential to re-engineering discodermolide so it can be utilized as a cancer treatment.  Likewise, other medications, agricultural solutions, and electronics advancements, are due to the works of these men, who created and re-created ways to use palladium-catalysed cross coupling in many applications.

The endeavor to break down carbon into single atoms, without waste materials attached to it, was first achieved by organic chemist Richard Heck in the late sixties, when he discovered that palladium could be used as a catalyst to link simple carbon atoms together without the waste.  What's more, the palladium would not stick around after the bonds were made; it would leave the carbon bond and go on to locate other carbon atoms in the test tube, continuing its work of joining them together.

The Heck reaction is an important principle for creating single bonds between carbon atoms. It has been used to create styrene, and more recently, to create medicines and substances for the electronics industry.

Heck used a chemical compound called olefins to activate the palladium atom to the carbon atoms.  Later, in 1977, Ei-ichi Negishi focused instead on activating the carbon atom, attaching zinc to it and thereby motivating the carbon atom to move to the palladium atom.  This process is known as the Negishi reaction.

Then in 1979, Akira Suzuki found that the element boron was a milder activator than zinc, and this was especially important to commercial synthesis.  Again, carbon activating, the Suzuki reaction uses boron to move the carbon atoms to the palladium atom.

The Heck, Negishi, and Suzuki reactions are used today as different applications of palladium-catalyzed cross-coupling reactions, all essential to the chemist's toolbox.

 

NobelPrize.com, A Powerful Tool For Chemists, MarineBiotech.org