news off the w e e k of IVAX, Miami, one of the generic firms involved in the battle. 'The ruling invali dates a majority of the patent claims asserted by Bristol-Myers, [and] has framed the issues for trial on the re maining ovarian-related patent claims." While Wall's decision clears the way for generic companies to market paclitaxel for treatment of some diseases, the manufacturers must first obtain FDA approval to market their versions of the drug. IVAX is the first company to file for FDA approval of generic paclitaxel, and expects to have its product on the market this summer. A spokeswoman for Bristol-Myers says the company "is considering its op tions," but would not comment on how generic competition will affect Taxol's sales. As a rule of thumb, though, a branded pharmaceutical will lose 75% of sales within 24 months of a generic al ternative coming to market. Ron Rogers
Achiral ligands abet chiral catalysis Based on a strategy they call "amplifica tion of the chiral environment," chemists at the University of Pennsylvania have de signed catalysts of enhanced enantioselectivity [/. Am. Chem. Soc, 122, 1802 (2000)]. By amplification, assistant pro fessor of organic chemistry Patrick J. Walsh and postdoctoral fellow Jaume Balsells mean that they use the center of asymmetry of one single-isomer catalyst ligand to force a second achiral ligand to adopt an asymmetric conformation.
MIT gets $350 million to decipher the brain It's not often that anyone gets a personal tour of a Massachusetts Institute of Technology laboratory led by university President Charles M. Vest (left). But this was a special occasion, a very special occasion. ΜΓΓ alumnus Patrick J. McGovern Jr. (second from left) and his wife, Lore Harp McGovern, had just given the school the wherewithal—a total of $350 million over the next 20 years, the largest known single gift to a university—to establish the McGovern Institute of Brain Research. McGovern, who received an S.B. degree in 1959, majored in life sciences with a special interest in neurophysiology. In 1964, he founded IDG, a computer publishing, research, and exposition management firm. IDG offers such ti tles as Computer World magazine and the popular " . . . For Dummies" series of books. Harp McGovern was cofounder of Vector Graphics, one of the earli est personal computer companies, and currently is involved with numerous start-up ventures in Silicon Valley. The institute will be headed by mo lecular biologist Phillip A. Sharp, 1993 Nobel Laureate in Physiology or Medicine. The mission, according to MIT, is "aggressive exploration of human learning and communication through interdisciplinary research that encompasses neuroscience, molecular neurobi ology, bioengineering, cognitive sciences, computation, and genetics." Chemistry also "has much to offer this important field," notes ΜΓΓ chemistry department chairman Stephen J. Iippard. "I am delighted" about the institute's establishment and "hopeful there will be many opportunities for chemists to participate in the activities of the institute and to collaborate with its members." Iippard is confident that "my colleague Phil Sharp will make the right connec tions with chemists." Janice Long
The resulting intensification of asym metry about the transition-metal ion that mediates the reaction increases the enantioselectivity of the catalyst. The tech nique offers possibilities for designing optimal catalysts via high-throughput screening of combinations of asymmetric and achiral ligands. Indeed, what sets their work apart from that of others who have combined chiral and achiral li— gands is that Walsh and Balsells have optimized the achiral ligand. Cyclohexane amplifies "I believe that this technique is ligand's chirality going to open a new chapter in the annals of asymmetric synthesis," R0 2 S N S0 2 R Penn organic chemistry professor N'/„ TiL2 ^_ Amos B. Smith III tells C&EN. \ Ν In other asymmetric catalyst li Ν / gands such as BINAP [2,2'-bis(diR02S \ phenylphosphino) -1, Γ-binaphthyl], S0 2 R the researchers note, the asymme CH CH try arises from the skewed arrange ΛΗ O - C H s L = ^ o—c ment of the naphthalene rings, which are remote from the metal H3C ion. That naphthalene ring asym Because ligand L is chiral, the interconmetry induces an asymmetric con verting chair conformations of cyclohex formation in the benzene rings at ane derivative are not mirror images. tached to phosphorus, which is the They serve to extend the chiral environ group that actually binds to metals. ment around the transition metal. Of their work, Walsh and Bal 2
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sells say: "In this contribution, we de couple the chiral and achiral portions of the ligand into two separate yet conformationally dependent ligands." Specifically, the Penn chemists use a catalyst that is a complex of titan ium (IV) with 2 moles of (S)-l-phenyl-lpropoxide and 1 mole of the 2,4-dimethylbenzenesulfonamide of as-l,2-diaminocyclohexane. The cis-diamide is a meso compound. Although the chair conformations of the cyclohexane deriv ative are chiral, normally they equili brate to an optically inactive mixture. But the asymmetry of the propoxide groups forces the cyclohexane ring to prefer one asymmetric conformation. In a model reaction in which />-tolualdehyde reacts with diethylzinc to form (R)-l-(4-methylphenyl)-l-propanol, the product forms in 84% enantiomeric ex cess. Although such an enantiomeric excess is not high enough for drug pro duction, for example, the technique al lows for further refining of the achiral li gand to increase enantiomeric excess. The Walsh group is going on to design catalysts for other types of asymmetric reactions. Stephen Stinson
