LeBel

The optical activity of quartz and certain other materials was first discovered by Jean-Baptiste Biot in 1815 in France, and in 1848 a young chemist in Paris named Louis Pasteur made a related and remarkable discovery. Pasteur noticed that preparations of optically inactive sodium ammonium tartrate contained two visibly different kinds of crystals that were mirror images of each other. Pasteur carefully separated the two types of crystals, dissolved them each in water, and found that each solution was optically active. Even more intriguing, the specific rotations of these two solutions were equal in magnitude and of opposite sign. Because these differences in optical rotation were apparent properties of the dissolved molecules, Pasteur eventually proposed that the molecules themselves were mirror images of each other, just like their respective crystals. Based on this and other related evidence, in 1847 van t Hoff and LeBel proposed the tetrahedral arrangement of valence bonds to carbon. 

Fig. 3.9 Proposed transition state for cyclopropanation with dioxahorolane 108. [Charette, A.B. juteau, H. Lebel, H. Molinaro, C.J. Am. Chem. Soc. 1998, 120, 11943. Reprinted with permission from The American Chemical Society]...

Poveda E, Rodes B, Lebel-Binay S, Faudon JL, Jimenez V, Soriano V (2005) Dynamics of enfuvir-tide resistance in HIV-infected patients during and after long-term enfuvirtide salvage therapy. J Clin Virol 34 295-301... 

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