ETHYL (S)-3-HYDROXYHEXANOATE synthesis

7synthesis methods

Product Name:ETHYL (S)-3-HYDROXYHEXANOATE
CAS Number:88496-71-3
Molecular formula:C8H16O3
Molecular Weight:160.21

3249-68-1 Synthesis

3249-68-1
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88496-71-3
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Yield:88496-71-3 100%

Reaction Conditions:

Stage #1: with triethylamine;dichloro(1,5-cyclooctadiene)ruthenium(II);(S)-(1,1'-binaphthalene)-2,2'-diylbis(diphenylphosphine) in toluene at 140; for 4 h;
Stage #2: ethyl butyroyl acetatewith hydrogen in methanol at 80; under 3345.86 Torr; for 5 h;

Steps:

4

Catalyst (2): Combine dichloro (1, 5-cyclooctadiene) ruthenium (117 mg, 0.417 mmol), (59-BINAP (300 mg, 0.482 mmol), and NEt3 (82. 5 pL, 0.59 mmol) in anhydrous toluene (13.5 mL) under N2. Heat the reaction mixture at 140° for 4 hours, and then cool to ambient temperature. Add THF to the resulting red jell, until a solution results. Concentrate the reaction mixture in vacuo, and add THF (30 mL) to the give the catalyst (1) in solution. This solution is used directly for the hydrogenation. (S)-3-Hydroxy-hexanoic acid ethyl ester: In a Fisher Porter tube, add the above catalyst (2) solution (10 mL) to a solution of ethyl butyrylacetate (25 g, 0.158 mol) in methanol (100 mL) under N2. Pressurize with H2 (50 psig) and heat at 80°C for 5 hours. Concentrate the reaction mixture ira vacuo. Purify the residue by vacuum distillation (25.0 g, 100%, 97.4 % ee). Chiral GC (30 m x 0.25 mm x 0. 25/im, BETA- Dex 225, 100°C) first eluting isomer, (18.72 minutes).

References:

WO2005/92835,2005,A1 Location in patent:Page/Page column 21