Issue Date: February 12, 2007
Yoshinori Yamamoto of Tohoku University, in Japan, is being honored for pioneering discoveries in synthetic organic and organometallic chemistry. He has focused on using Lewis acids and transition metals as catalysts and reagents, as well as on their application to total synthesis of complex, biologically active natural products.
His studies of Lewis acids have led to stereochemically controlled condensations of allylic organometallics with aldehydes, ketones, and imines, which are now routinely used. In the 1980s, people believed that the condensation proceeds through a cyclic six-membered transition state and that the stereochemistry of the products is dictated by the stereochemistry of the starting allylic organometallics. Yamamoto's work showed that in the presence of a Lewis acid, the condensation reaction proceeds through an acyclic transition state and that the stereochemistry of the products is not dictated by the stereochemistry of the starting substrates. This finding was applied to the total synthesis of the giant natural products gambierol (18 stereocenters) and brevetoxin B (23 stereocenters).
Yamamoto also figures prominently in the study of palladium-catalyzed reactions. According to a colleague, he "is one of the real world leaders" in this field. Specifically cited as important is his pioneering use of bis-pi-allylpalladium reagents, whose nucleophilic reactivity complements the electrophilicity of well-known pi-allylpalladium compounds. He also developed palladium-catalyzed benzannulation and pronucleophile addition.
More recently, he developed gold-catalyzed benzannulation, which has contributed to the increasing popularity of gold- and platinum-catalyzed reactions in organic synthesis.
Early in Yamamoto's career, it was not obvious that he would specialize in development of synthetic methods. His Ph.D. studies at Osaka University centered on the physical organic chemistry of carbenes and their spectral characterization. But for postdoctoral training, he joined the group of the late Herbert C. Brown at Purdue University.
In Brown's lab, Yamamoto says, he learned organic synthesis, organoborane chemistry, and organometallic chemistry. "I realized that organic synthesis, rather than physical organic chemistry, fit me well," Yamamoto recalls. "I had the impression that organic synthesis would be more important and pragmatic than physical organic chemistry."
He adds that he learned many other things from Brown, such as the skills for handling organoboranes and organometallic compounds and, more important, how to conduct research systematically, summarize results, and write research papers.
Yamamoto, 64, received B.S., M.S., and Ph.D. degrees from Osaka. Immediately after completing his Ph.D. in 1970, he joined Brown's lab as a research associate, even as he held an instructor position at Osaka. He returned to Osaka in 1972 and served as an instructor there until 1977, when he joined Kyoto University as an associate professor. In 1986, he moved to Tohoku as a professor in the Graduate School of Science.
In addition to his academic appointment at Tohoku, Yamamoto also served as the director of the university's analytical center from 1990 to 1996, director of the Research & Analytical Center for Giant Molecules from 2003 to 2006, and vice president of the university beginning in 2006.
Yamamoto is a member of the American Chemical Society, the Chemical Society of Japan, the Kinki Chemical Society, the Royal Society of Chemistry, and the Society of Synthetic Organic Chemistry of Japan. He is also a member of the editorial advisory boards of various journals, including Tetrahedron, Tetrahedron Letters, and Synlett.
Among his numerous awards are the Alexander von Humboldt Research Award, in 2002; the Award of the Chemical Society of Japan, in 1996; and the Award of the Chemical Society of Japan for Young Chemists, in 1976.
To relax, Yamamoto likes to walk on forest and park trails. He also enjoys climbing mountains, including Mount Fuji and the Japanese Alps.
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