advanced separation chemistry for life sciences Fluorous chemistry lecture slides courtesy of These slides are provided to the academic community in the interest of promoting scientific awareness of this new area of chemistry. They may be freely used and adapted for instructional purposes. FTI encourages you to forward them to colleagues. Please include this informational cover slide when forwarding. These slides and their components may not be used in commercial activities or in publications without prior permission from FTI. Research attributions, where they appear, must always accompany individual slides. Background graphics and other decorative clutter are omitted in case you want to apply your own graphic standards. Notes are attached to each slide. We appreciate (but do not require) acknowledgement when these slides are used. For more information, questions or comments, contact FTI at or contact- Additional slides with fluorous reaction examples are also available. Protein structure courtesy Protein Data Bank, PDB ID 152L, J.Zhang,B.Matthews

Introduction to fluorous chemistry Fluorous molecules comprise an organic domain and a highly fluorinated domain. Ideally, the organic domain controls reactivity and the fluorinated domain controls separation. The aim is to facilitate separation.

Development of fluorous chemistry 1991Thesis by Vogt (Univ. of Aachen) on the use of perfluorinated ethers to immobilize homogeneous catalysts 1993Zhu (3M) reported on azeotropic separations using perfluorocarbon solvents 1994Seminal paper by Horváth & Rabai (ExxonMobil) in Science described the use of heavily-fluorinated compounds in fluorous solvents for hydroformylation: biphasic catalysis. Term “fluorous” is introduced. 1999Curran (Univ. of Pittsburgh) develops “light” fluorous chemistry. The less-fluorinated compounds were soluable in organic and hybrid solvents, making fluorous techniques more practical in organic synthesis. 2000Fluorous Technologies, Inc. founded to commercialize light fluorous chemistry. 2004Peters et al (GNF/Novartis) report use of fluorous tags for protein enrichment in proteomics applications.

Two basic approaches Fluorous compounds with integral (permanent) fluorinated domains: Fluorous compounds with removable (temporary) fluorinated domains (tags):

“Heavy” versus “light” Generally, > 60% fluorine by weight is called a “heavy fluorous” compound. These materials have limited solubility in non-fluorous media, typically require perfluorinated solvents, and are expensive - all of which limits practical adoption. “Light fluorous” compounds (< 40% by weight) are miscible in organic solvents and cost less. Since they typically will not form a separate fluorous liquid phase, light fluorous compounds are separated using a companion fluorous stationary phase.

Liquid-liquid extraction A heavy fluorous technique Whereas compounds bearing light fluorous tags are miscible in organic solvents, heavy fluorous compounds are soluble in perfluorinated solvents and form a distinct liquid phase. This can be exploited if a liquid-liquid separation is preferable, although reactivity is limited to the phase interface. organic aqueous fluorous

Light fluorous separation is an affinity technique A fluorous sorbent is a chromatographic packing material modified with a highly fluorinated domain. Fluorous stationary phases exhibit high selectivity for retention of fluorous versus non-fluorous molecules. In addition, fluorous sorbents are able to resolve fluorous molecules of differing fluorine content (e.g. different size or number of fluorous tags).

1.Load sample 2.Fluorophobic wash to remove organics: e.g. MeOH-H 2 O (85:15) 3.Fluorophilic wash to elute fluorous species: e.g. THF fluorous dyenon-fluorous dye Solid-phase extraction 123 A light fluorous technique 1. Curran, D. P.; Hadida, S.; He, M. J. Org. Chem. 1997, 62, Curran, D. P. Synlett. 2001, 9, 1488.

Fluorous HPLC example: separaration by fluorine content C 7 H 15 C3F7C3F7 C4F9C4F9 C 5 F 11 C 6 F 13 C 8 F 17 C 7 F 15 C 9 F 19 C 10 F 21 80:20 MeOH: H % MeOH Minutes C n F 2n+1

Fluorous-adapted organic synthesis Ionic Enolate, Grignard, lithiate, cationic Free Radical Cyclization, dehalogenation, deoxygenation Lewis Acidic Friedel-Crafts acylation, BBr 3 Transition metal catalyzed Suzuki, Heck, Buchwald, Stille, Co, Rh Reduction/oxidation LAH, hydrogenation, H 2 O 2, Swern Chemical reaction compatibility

Applications in organic synthesis The Mitsunobu Reaction S. Dandapani, (Fluorous Technologies); unpublished work

Comparative NMR’s using combinations of organic & fluorous reagents Prod TTPO DEH Prod TTPO DEH TTP + DEADTTP + F DEAD F TTP + DEAD F TTP + F DEAD Slide courtesy Prof. D. P. Curran

Fluorous scavenging a solution-phase fluorous application Curran, D., Zhang, w., et al., Tetrahedron, 2002, 58, 3871

Biopolymer purification an emerging fluorous application MeOH + H 2 O Overkleeft, H.S., et al. Tetrahedron Letters 2003, 44, Add fluorous tag Cleave from resin, deprotect side chains, then SPE Clean product Unwanted organics Tagged product Capped deletion sequence Detag, then SPE

Fluorous biphasic catalysis 1. T. Horvath, J. Rabai, Science 1994, 266, Olofsson, K.; Kim, S. Y.; Larhed, M.; Curran, D. P.; Hallberg, A., J. Org. Chem. 1999, 64, Fluorous-tagged ligands enable reliable L-L separation of catalyst – important for toxic and/or expensive catalysts. Variation shown here is thermomorphic fluorous biphasic catalysis. Solubility of the fluorous species in organic phase is promoted with heat, improving kinetics.

hexane C 6 F 11 CF 3 warm react cool + separate phases 1. T. Horvath, J. Rabai, Science 1994, 266, Horvath, I. T. Acc. Chem. Res. 1998, 31, 641. Hydroformylation with a fluorous Wilkinson's catalyst Fluorous biphasic catalysis

Fluorous triphasic separation One of the two enantiomers (which are intermixed) is fluorous- tagged Only the (S) enantiomer is soluble in the fluorous phase; it migrates while (R) stays behind The receiving phase contains a reagent to remove the fluorous tag, leaving a clean (S) product. The tag itself prefers to be in the fluorous phase and migrates back there, where it accumulates. Source phase Receiving phase Fluorous phase Chiral separation of 2-Napthylethanol Curran, D. P. et al. Organic Letters 2002, 4, 15,