Robert Burns Woodward
Robert Burns Woodward
Robert Woodward was a Nobel Prize-winning chemist who developed numerous techniques for producing complex chemical compounds in the laboratory. Many of the methods he developed are used today to produce compounds that were once only obtainable from living organisms.
Woodward was born in Boston, Massachusetts, in 1917. His childhood interest in science prompted his mother to give him a chemistry set. By the time he was in high school, he was conducting experiments in his home that were similar to those performed in college chemistry classes. Woodward began attending college at the Massachusetts Institute of Technology when he was only sixteen. He rarely went to class, however, usually only showing up for final exams. Instead, he spent his time in the school's chemistry laboratories and the library. He earned his degree in three years and a doctorate in chemistry in one year. After graduating, Woodward spent a summer teaching at the University of Illinois. He spent the remainder of his career teaching chemistry at Harvard University.
Woodward specialized in organic chemistry. Organic chemistry is the study of compounds containing the element carbon. Most compounds that make up plants, animals, and other organisms contain this element, so organic chemistry is largely the chemistry of living things. When Woodward began teaching at Harvard, the field of organic synthesis was still in its infancy. Synthesis involves the use of chemical reactions to produce complex compounds from simpler starting materials. Chemists use synthesis to produce useful compounds in the laboratory.
Woodward focused his attention on stereochemistry and the synthesis of specific stereoisomers. Stereochemistry is the study of the three-dimensional arrangement of the atoms of compounds. Two compounds that are identical except for the way their atoms are arranged in space are said to be stereoisomers. Each stereoisomer of a compound has unique chemical properties. Many of the compounds that make up living things are stereospecific; that is, the organism produces only one particular stereoisomer of a compound. Woodward developed methods not only for synthesizing particular organic compounds but also for isolating specific stereoisomers of the compounds.
In 1944 Woodward and fellow chemist William Doering (1917- ) were the first to synthesize the compound quinine. Quinine is used to treat the mosquito-carried disease malaria. Before quinine was made in the laboratory, it had to be obtained from the bark of South American cinchona trees. Woodward went on to synthesize many other stereospecific organic compounds, including cortisone (a human hormone), cholesterol, reserpine (a tranquilizing drug that was once obtained from the roots of certain tropical plants), chlorophyll, and cephalosporin C (an antibiotic). In 1971, after working for ten years with a team of more than one hundred researchers, he completed the synthesis of vitamin B12. Woodward won the Nobel Prize for chemistry in 1965 for his many syntheses of organic compounds.
Synthesizing such complex organic chemicals required many steps and intermediate compounds. (The synthesis of vitamin B12 required more than one hundred chemical reactions.) Woodward often was able to envision the entire sequence of reactions needed to produce complicated organic compounds before he ever began work in the lab. Many of the syntheses Woodward performed were among the most complicated up to that time. Several of his syntheses formed the basis for drug-manufacturing procedures, such as that used for reserpine.
In 1965 Woodward and the chemist Roald Hoffmann (1937- ) proposed a set of rules that could be used to predict the stereochemistry of the products of a chemical reaction. Today these rules are known as the Woodward-Hoffmann orbital symmetry rules. They helped explain the sometimes unexpected stereochemical results Woodward had observed during his syntheses. This work won Hoffmann a Nobel Prize in 1981. Woodward most likely would have shared the prize if not for his death in 1979.
STACEY R. MURRAY