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Table 2 Solvent effect on the optimization of enzymatic kinetic resolution of acetylenic alcohol 3

From: Chemoenzymatic construction of chiral alkenyl acetylenic alcohol, a key building block to access diastereoisomers of polyacetylenes

Entry Solvent Log P t (h) Conversion (%) a ( R )-3 b ( S )-11 b E c
% e.e. % e.e.
1 Dioxane −1.10 1.5 4 2.2 58.0 4
2 CH3CN −0.33 1.5 22 23.3 95.2 51
3 Acetone −0.23 1.5 15 20.6 80e 11
4 THF 0.49 1.5 13 10.0 84.5 13
5 Et2O 0.85 1.5 46.6 78.7 95.0 94
6 tBuOMe 0.96 1.5 45 76.4 97.0 152
7 Toluene 2.50 1.5 49.3 91.1 96.6 185
8 n-Hexane 3.50 0.5 56 96.0 97.7 340
9 n-Octane 4.50 0.5 51.1 89.0 97.9 284
10 n-Hexane 3.50 6 60.0 96.0 64.2 17
11 n-Octane 4.50 6 54.3 98.4 96.2 300
12 Et2O 0.85 6 52.9 97.7 89.2 78
13 tBuOMe 0.96 6 52.4 98.4 91.6 109
14 Toluene 2.50 6 50.3 98.4 97.3 354
15d Toluene 2.50 6 50.3 97.4 97.3 319
  1. Reaction conditions: rac-3 (30 mg, 0.1 mmol), Novozym 435 (20 mg, 67% w/w, 1,000 U/mmol), vinyl acetate (62 μL, 6.6 equiv), solvent (1 mL), R.T. aConversion (C) was determined by HPLC (Chiralcel AS-H; flow rate: 0.50 mL/min; iPrOH/n-hexane: 1/99; temperature: 25°C; UV: λ = 199 nm); bthe determination of enantioselectivity (HPLC Chiralcel AS-H) and the absolute configuration (Mosher's method) of 3 are illustrated in Additional file 1; c E = ln[(1 − e.e.S)(1 − C)]/ln[(1 + e.e.S)(1 − C)], where e.e.S represents the enantiomeric excess of the recovered alcohol; d257 mg of rac-3 was applied, see the Experimental section for details; esince considerable side products were contaminated, the HPLC determination (80% e.e.) of (R)-3 was not calibrated.