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

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence