Reaktion #957461

Reaktionsgleichung

HCl

dimethyl succinate

4-(tert-butyl-dimethyl-silanyloxy)-cyclohexanecarbaldehyde

potassium tert-butoxide

tert-butanol

→

title compound

Ausbeute 38.3%

2-[4-(tert-Butyl-dimethyl-silanyloxy)-cyclohexylmethylene]-succinic acid 1-methyl ester

Ausbeute 38.3%

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooled to RT
2. 2
   Einengenconcentrated under vacuum
3. 3
   workup.DISSOLUTIONThe residue was dissolved in water (25 mL)
4. 4
   Waschenwashed with EtOAc (2×10 mL)
5. 5
   Extraktionextracted with EtOAc (2×20 mL)
6. 6
   Trocknendried (Na2SO4)
7. 7
   Einengenconcentrated
8. 8
   SonstigeThe crude product was purified by flash chromatography (25% EtOAc/DCM)

Vorschrift

A solution of dimethyl succinate (730 mg, 5.0 mmol) and 4-(tert-butyl-dimethyl-silanyloxy)-cyclohexanecarbaldehyde (1.00 g, 4.1 mmol) was added over 25 min to a 1.0M solution of potassium tert-butoxide in tert-butanol (4.4 mL. 4.4 mmol). The reaction mixture was heated at 50° C. for 50 min, cooled to RT and concentrated under vacuum. The residue was dissolved in water (25 mL) and washed with EtOAc (2×10 mL). The aqueous layer was acidified with 6 N HCl (2.0 mL, 12 mmol) and extracted with EtOAc (2×20 mL), dried (Na2SO4) and concentrated. The crude product was purified by flash chromatography (25% EtOAc/DCM) to give the title compound (560 mg) as a mixture of olefin isomers (˜1:1) and a mixture of cis and trans isomers at the cyclohexyl ring (˜1:1). 1H NMR (CDCl3, 400 mHz) δ (ppm) olefin peaks at 6.88 (d, J=10.2 Hz) 6.77 (d, J=10.0 Hz) CHOTBS peaks at 3.96 ppm (br s) (cis isomer, hydrogen equitorial, 3.55 (m) (trans isomer, hydrogen axial).

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