1 Electronic Supporting Information for A Genetic Selection System for Evolving Enantioselectivity of Enzymes Manfred T. Reetz*, Horst Höbenreich, Pankaj Soni, Layla Fernandez Synthesis of the compounds Commercial compounds were purchased as indicated in parentheses and used as obtained: (R)-isopropylidene glycerol, (S)-isopropylidene glycerol, rac-isopropylidene glycerol, acetic anhydride, 4-(N,N-dimethylamino) pyridine, N,N-dimethyl formamide (all Fluka), sodium fluoroacetate (Merck) and triethylamine (Acros). All other chemicals were purchased from Aldrich. All reactions were performed using dry solvents and magnetic stirring. Inert atmosphere was created by heating the glassware under vacuum (< 5*10 -2 mbar) and three rounds of evacuation /Ar-flush. Flash column chromatography was performed using Merck silica gel 60 (230-400 mesh) and glass columns of appropriate size (resulting fill level: 50-100%). A Büchi GKR-51 apparatus was used for Kugelrohr-distillation. 1 H and 13 C (H-decoupled) nuclear magnetic resonance spectra (NMR) were recorded on a Bruker AV400. All chemical shifts (δ) were quoted in parts per million (ppm) and are reported relative to an internal standard (tetramethylsilane, δ = 0.0). The following abbreviations for multiplicities were used: s, singlet; d, doublet; m, multiplet. Mass spectra (MS) were measured on a Finnigan MAT 8200 (Electron Ionization, 70 eV). Gas chromatography (GC) was performed on a Hewlett-Packard HP6890 with a flame ionization detector (FID). Compounds and absolute configuration of enantiomers were determined by comparison with standards. (S)-Isopropylidene glycerol acetate [(S)-1] 5.20 g (R)-isopropylidene glycerol (IPG; 39.5 mmol) was dissolved in 75 ml dry dichloromethane. Then 8.00 g triethylamine (79.0 mmol), 8.06 g acetic anhydride (79.0 mmol) and 0.37 g 4-(N,N-dimethylamino) pyridine (DMAP) were added and the reaction stirred for 18 h at room temperature. The solvent was removed and the product isolated by flash column chromatography (200 g silica gel; hexane: ethyl acetate = 20:1; R f = 0.13). For further purification the product was distilled (Kugelrohr; 23 mbar; 125 °C). Yield: 5.29 g of a colorless liquid (76.8%). 1 H-NMR (CDCl 3 ) δ = 1.37 (s, 3H, CH 3 -C), 1.44 (s, 3H, CH 3 -C), 2.05 (s, 3H, CH 3 -COO), 3.73 (m, 1H, O-CH (H) –CH-O), 4.05-4.20 (m, 3H), 4.33 (m, 1H, CH -CH 2 -OOC). 13 C-NMR (CDCl 3 ) δ = 21.0, 25.6, 26.5, 63.6, 66.6, 74.1, 110.0, 171.0. MS (EI): m/z (rel%) = 43(85), 57(8), 72(15), 101(40), 159(100), 173 (<1). GC: enantiopure Program: Instrument: Hewlett Packard 6890 Column: 25 m Ivadex 1/OV 1701 G/294 Gas: 1.0 bar H 2 Temperature program: 10 min iso. 100 °C. Inlet/ injector temp.: 250 °C / 320 °C Retention time: 4.19 min [(S)-IPG-Ac] O O O O Supplementary Material (ESI) for Chemical Communications This journal is (c) The Royal Society of Chemistry 2008