tree were achieved in the late 1980s by Cope Award winner Corey. The complex compounds are found in herbal extracts, whose sales are booming. Yet another Cope medalist, Columbia University chemistry professor Koji Nakanishi, carried out a preliminary investigation of ginkgolide biosynthesis in the 1970s, based on the degradation of metabolites of radiolabeled precursors. Arigoni and colleagues revisited the problem, developing an efficient biological system that allowed them to use nuclear Arthur C. Cope Award magnetic resonance (NMR) spectroscorecipients py to study the incorporation of precursors labeled with stable isotopes. 1973 Robert B. Woodward and Roald Hoffmann "We soon found out that something 1974 Donald J. Cram very fishy was going on in that plant," 1976 E. J. Corey Arigoni said. Nakanishi had assumed 1978 Orville L. Chapman that the ginkgolide biosynthesis fol1980 Gilbert J. Stork lowed the well-known acetate/mevalon1982 Frank H. Westheimer ic acid (MVA) pathway to isopentenyl 1984 Albert J. Eschenmoser 1986 Duilio Arigoni pyrophosphate (IPP), the key interme1987 Ronald Breslow diate of terpene biosynthesis. But the 1988 Kenneth B. Wiberg ETH researchers found carbon-13 in1989 William S. Johnson corporation patterns that did not jibe 1990 Koji Nakanishi with that familiar route. 1991 Gerhard L. Closs Instead, Arigoni's group identified 1992 K. Barry Sharpless 1993 Peter B. Dervan deoxyxylulose as the precursor of the 1994 John D. Roberts IPP units in the ginkgolides. Other re1995 George M. Whitesides searchers had earlier observed the 1996 Robert G. Bergman same anomalous biosynthesis of ter1997 Ryoji Noyori penes in bacteria, but the ETH team was 1998 Samuel J. Danishefsky the first to recognize it in plants. 1999 Ralph F. Hirschmann The biggest surprise, Arigoni said, was finding that the ginkgo uses two inalists' endeavors. For example, Duilio dependent pathways for the early steps Arigoni, chemistry professor emeritus of terpene biosynthesis: In the cytosol, at ETH, presented his insights into the the MVA route leads to sterols, while in biosynthesis of the ginkgolides. The organelles the deoxyxylulose pathway first laboratory syntheses of these un- produces the ginkgolides and a related usual diterpenes from the Ginkgo biloba 15-carbon compound, bilobalide.
Symposium Celebrates 25 Years Of Cope Awards
Talks by past Cope medalists reveal organic chemistry's rich diversity Pamela S. Zurer C&EN Washington
From the ACS meeting " A
