Organic Chemistry is the scientific discipline that is focused on constructing organic molecules (molecules that contain carbon).  Because carbon is the skeleton that undergirds so many of the molecules we interact with on a daily basis (medicines, vitamins, organic LEDs, proteins, nucleic acids, etc.), new ways of easily constructing carbon-carbon bonds are especially valuable.  One type of reaction known as Pd-catalyzed cross-coupling reactions has made it even easier for chemists to construct carbon-carbon bonds in a reliable, convenient, and intuitive way.  The 2010 Nobel Prize in Chemistry was awarded to three chemists in recongition of their contributions to this field of Pd-catalyzed cross couplings: Prof. Richard Heck (Heck Coupling), Prof. Ei-ichi Negishi (Negishi Coupling), and Prof. Akira Suzuki (Suzuki-Miyaura Coupling).  The Suzuki-Miyaura Reaction in particular is now one of the top five most utilized carbon-carbon bond forming reactions used in the pharmaceutical industry because of its convenience and versatility.

The Suzuki-Miyaura Cross Coupling uses as starting materials an aryl boronic acid (molecule in red) and an aryl bromide (molecule in blue).  The carbon bearing the boron will ultimately be attached to the carbon bearing the bromine.  

There are several advantages presented by this choice of partners.

• Aryl bromides (aryl halides) are relatively abundant (it has been calculated that over 10,000 structural variations of aryl bromides can be purchased commercially, while even more can be synthesized from other precursors).  

• Boronic acids are also very abundant as well (over 10,000 structural variations of the boronic acid are also available commercially)

• With 10,000 of each component commercially available, this means we can imagine (as a rough estimate) 10,000 x 10,000 = 100,000,000 Suzuki-Miyaura Cross Coupling products that could be made in a single step!  Maybe not surprisingly, this is exactly what is done in the pharmaceutical industry to create modifications of a particular lead compound in search for a more active drug compound.  

• Boronic acids also have the advantage that they are relatively non-toxic.  As an illustration, the cleaning agent Borax contains sodium tetraborate and is relatively non-toxic.  This is particulary important because other cross-coupling reactions can use much more toxic coupling partners (e.g. the Stille Coupling uses tributyl tin, which is much more toxic).  If you are making a pharmaceutical drug, then you will need to be concerned about residual toxic metals like tin when you purify your final drug.  

For all these reasons (and probably more), the Suzuki-Miyaura Coupling is a widely-adopted reaction.  We'll be exploring this reaction in our Science 10 class!