SCIENCE & TECHNOLOGY
FLUOROUS BEGINS TO FLOURISH Symposium spotlights diverse range of fluorous technologies spanning chemistry and biology MICHAEL FREEMANTLE, C&EN LONDON
T
HE TENTACLES OF FLUOROUS
chemistry now reach beyond traditional organic chemistry into other realms such as supramolecular c h e m i s t r y , biology, a n d medicine. Current and potential applications include biphasic catalysis, natural product synthesis, oligonucleotide purification, and pulmonary disease therapy
are typically perfluoroalkyl groups. T h e y can b e p e r m a n e n t or t e m p o r a r y attachments, depending on the application. Fluorous compounds not only mimic the chemical reactivity of their nonfluorous counterparts b u t also, because of the tags, prefer to dissolve in fluorous solvents rather than in organic solvents or water. This combination of properties has proved useful for
In a seminal paper on the topic, Horvâth and Jozsef Râbai, a visiting scientist from Eôrvos Lorând University, described t h e use of a trialkylphosphine-modified rhodiu m catalyst with a fluorous tag o n each of the three alkyls for the preparation of aldehydes {Science 1 9 9 4 , 266, 72). T h e reactions —hydroformylation of olefins such as 1-decene—were carried out in a biphasic system consisting of a fluorous phase and a conventional organic solvent as the other phase. After the reaction, the tagged catalyst remained in the fluorous phase, allowing it to be reused, and the aldehydes were extracted from the other phase.
THIS DISCOVERY was "a real catalyst for the development of fluorous technologies," Vincent said at t h e Bordeaux symposium. In recognition of the work, H o r v â t h and Râbai received the first international award for fluorous technologies at the meeting. "Soon after the paper by H o r v a t h and Râbai, other examples of the use of fluorous biphasic catalysis apOrganic phase Organic phase Pyr = + THF peared," Fish told C & E N . " T h e t e c h n i q u e has n o w Impurities b e e n a d a p t e d for almost Fluorous phase Fluorous phase Organic phase every classic organic reaction, including t h e h o m o geneous oxidation of alcoImpurities Cu-F = hols and alkenols and t h e -|
