Knowles Dies At 95

William S. Knowles, 95, a retired senior Monsanto chemist who shared the Nobel Prize in Chemistry in 2001 for his pioneering work in asymmetric catalysis, died on June 13 in Chesterfield, Mo., of complications of Lou Gehrig’s disease.

In the late 1960s, Knowles worked to develop a catalyst that could be used to synthesize individual enantiomers of chiral compounds directly, without having to separate them from racemic mixtures. Subsequently, he led a team of researchers who developed chiral phosphine ligands that proved effective in the enantioselective synthesis of the amino acid l-dopa, which is used to treat Parkinson’s disease. He retired in 1986 after 44 years with Monsanto.

Knowles shared half of the Nobel Prize with Ryoji Noyori of Nagoya University, in Japan, for their work on chirally catalyzed hydrogenation reactions. The other half of the prize went to K. Barry Sharpless of Scripps Research Institute for his work on chirally catalyzed oxidation reactions.

Born in Taunton, Mass., Knowles earned a B.S. in chemistry from Harvard University in 1939 and a Ph.D. in chemistry from Columbia University in 1942 under Robert C. Elderfield.

He then began working for the Thomas & Hochwalt Laboratories in Dayton, Ohio, which had recently been acquired by Monsanto. Two years later, he was transferred to St. Louis to research plasticizers and intermediates for Monsanto before working on the total synthesis of steroids. During his career, he rose through the ranks in a line of advancement the company had established for those who wanted to keep working in laboratory research.

Knowles had been a member of ACS since 1940. He embraced environmental causes and enjoyed fly-fishing, hiking, and biking.

Knowles is survived by his wife of 66 years, Nancy; three daughters, Lesley McIntire, Elizabeth, and Sarah; one son, Peter; and four grandchildren.