Chemical Synthesis

One of my failings as a chemist has been my relative lack of interest in synthesis. As someone who has spent his entire professional life involved with aspects of the chemistry enterprise, I have heard it said innumerable times that what sets chemistry apart from other sciences is its ability to make things. While I know that’s true, synthesis has never held a great fascination for me.

That said, sitting through two days of talks on the frontiers of organic synthesis at the 2009 Welch Symposium last week in Houston reminded me of the incredible creativity of synthetic organic chemists. It reminded me also of the contributions of synthetic chemistry to the quality of life we enjoy.

“Synthetic chemistry in the 21st century is not just a great intellectual challenge, it is essential for addressing the many challenges that face humanity,” said Peter B. Dervan, a chemistry professor at California Institute of Technology and organizer of this year’s symposium.

The lineup of synthetic organic chemists assembled for the symposium by Dervan was outstanding, including several of the brightest young stars in the field. Their talks covered topics such as asymmetric catalysis, cross-coupling methodology, highly selective carbon-hydrogen bond activation, and synthesis of complex natural products.

A number of themes emerged from the talks. The most important, perhaps, is the most obvious: As Dervan noted in his introduction to the symposium, the field of synthetic organic chemistry remains a vibrant core discipline within the chemistry enterprise. Advances are absolutely essential for continued progress in creating molecules to advance human well-being.

Another theme was an increasing emphasis among synthetic chemists in emulating nature in creating complex molecules. Stanford University associate professor of chemistry Justin Du Bois, for example, said, “Like most of my friends who have spoken here, I have for many years been inspired by how nature does chemistry.” Du Bois pointed out that, to create many complex molecules, nature first builds the framework of the molecule and then does “surgery” on that framework—adding functionality selectively—to create the specific compound.

M. Christina White, an associate professor of chemistry at the University of Illinois, Urbana-Champaign, noted that, “All of the molecules of life are oxidized hydrocarbons.” She observed that a challenge facing synthetic chemists is learning to selectively insert oxygen, nitrogen, and carbon atoms into carbon-hydrogen bonds.

That the focus of the Welch Symposium in a given year is disconnected from the selection of that year’s Welch Award recipient could not have been clearer than in 2009. This year’s Welch Award went to Caltech’s Harry B. Gray, one of the world’s most influential inorganic chemists.

Gray’s talk fell into the category that Monty Python would label, “And now for something completely different.” After a day and a half of talks that focused on reactions geared toward creating highly complex molecules, Gray led off with two simple equations:

2H₂O → O₂ + 4H⁺ + 4e^-

and

O₂ + 4H⁺ + 4e^- → 2H₂O

which he described as the two most important reactions on Earth because they represent the basis of, first, photosynthesis, and, second, respiration.

Gray described his work over the past 30 years to understand the chemistry and physics that underpin how electrons transfer rapidly through proteins to specific destinations to generate the energy flow that sustains life. He also discussed his current efforts to use this knowledge to understand photosynthesis and create an inexpensive and efficient artificial photosynthetic system for the production of fuels from sunlight and water.

As Dervan pointed out, it has been nearly a decade since a Welch Symposium focused on synthetic organic chemistry. From the talks given at this year’s symposium, it is obvious that the field is alive and well and in very good hands. (For a detailed program of the Welch Symposium, including biographies of all the speakers, go to www.welch1.org/ChemicalConference/2009Program4.pdf.)

Thanks for reading.

Rudy Baum
Editor-in-chief