Ph.D. chemistry graduate of The Chinese University of Hong Kong, Dr. Yeung Ying-yeung discovered a new organic synthesis that would substantially reduce the cost of production and improve the supply of Tamiflu. The discovery was made under the guidance of Prof. Elias James Corey, 1990 Nobel laureate in chemistry. Dr. Yeung is a post-doctoral fellow at Prof. Corey's laboratory at Harvard University. The breakthrough was reported in the influential Journal of American Chemical Society.
Fear of an avian flu pandemic has prompted governments around the world to stockpile the antiviral drug oseltamivir phosphate, better known as Tamiflu. However the natural compound for its synthesis is rare and the synthetic pathway is long, making it difficult to ramp up production. At present Tamiflu is made in a 14-stage process by first extracting shikimic acid from the Chinese star anise fruit. Chinese star anise is expensive and limited in supply. Besides the drug can only be made in small quantities at a time because the process involves a highly explosive chemical.
Under Prof. Corey's guidance, Dr. Yeung and his research co-workers avoided the use of shikimic acid by using an asymmetric catalytic step early in the synthesis to create a key building block.
'Our synthetic pathway has several advantages over the current production method,' said Dr. Yeung. 'Our method is more efficient. It takes only 11 steps and uses inexpensive and readily available starting materials—1,3-butadiene and 2,2,2-trifluoroethyl acrylate. We have also avoided using the highly explosive chemical azides which is dangerous and slows down the synthesis process.'
This new synthesis process was reported in the influential Journal of American Chemical Society. Dr. Yeung hopes that his experience will encourage others to work on different ways of synthesizing Tamiflu. 'Although the current supply of Tamiflu has grown, it is still expensive. We hope to reduce the drug's price and increase its supply further so lives can be saved, especially in poor countries.'
Dr. Yeung obtained his BS in chemistry from CUHK. His keen interest in research was evident when he had a paper published in Journal of Organic Chemistry (2001, 66, 1910) as an undergraduate research assistant under Prof. Chow Hak-Fun. Dr. Yeung went on to pursue a Ph.D. in anti-cancer natural molecule synthesis under Prof. Tony Kung-ming Shing.
His interest and perseverance were reflected in the excellent quality of his research. Part of his Ph.D. thesis, which describes the total synthesis of a complex quassinoid, Samaderine Y, an antitumor agent, was published in a top chemistry journal (T. K. M. Shing and Y. Y. Yeung, Angew. Chem. Int. Ed. 2005, 44, 7981-7984).
Dr. Yeung was offered a postdoctoral fellowship by Prof. Corey 18 months before his Ph.D. graduation in 2005 whereupon he joined the Department of Chemistry and Chemical Biology of Harvard University. Dr Yeung's successful career in organic chemistry shows to secondary school students that with passion and hard work, a pure science concentration can result in a rewarding career.