Reaktion #2259469

Reaktionsgleichung

1-bromo-2-iodo-4-(trifluoromethyl)benzene

tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate

potassium carbonate

→

tert-butyl 4-(2-bromo-5-(trifluoromethyl)phenyl)-5,6-dihydropyridine-1(2H)-carboxylate

Ausbeute 73.1%

Lösungsmittel

ethyl acetate

dioxane

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Waschenwashed with water
2. 2
   ExtraktionThe aqueous layer was extracted with ethyl acetate
3. 3
   Trocknenthe combined organic layers were dried with sodium sulfate
4. 4
   Filtrationfiltered
5. 5
   Einengenconcentrated
6. 6
   SonstigeThe material was purified via column chromatography (silica gel 80 g, gradient elution 0 to 100% Et2O:Heptane)

Vorschrift

A solution of 1-bromo-2-iodo-4-(trifluoromethyl)benzene (1.408 ml, 8.55 mmol), tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate (Frontier Scientific, Logan, Utah, 2.78 g, 8.98 mmol), Pd(dppf)Cl2—CH2Cl2 adduct (Strem Chemicals Inc., Newburyport, Mass., 0.349 g, 0.427 mmol), and potassium carbonate (2.052 g, 34.2 mmol) in dioxane (32.1 ml) and water (10.69 ml) was stirred at 70° C. for three hours. (LC-MS MH+ 430.1) The reaction was diluted with ethyl acetate and washed with water. The aqueous layer was extracted with ethyl acetate, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via column chromatography (silica gel 80 g, gradient elution 0 to 100% Et2O:Heptane) to afford tert-butyl 4-(2-bromo-5-(trifluoromethyl)phenyl)-5,6-dihydropyridine-1(2H)-carboxylate (2.54 g, 6.25 mmol) as a light yellow oil. [M+H]+=428.0. 1H NMR (400 MHz, CHLOROFORM-d) δ ppm=7.69 (d, J=8.3 Hz, 1H), 7.43 (d, J=2.2 Hz, 1H), 7.41-7.36 (m, 1H), 5.69 (br. s., 1H), 4.08 (q, J=2.7 Hz, 2H), 3.66 (t, J=5.6 Hz, 2H), 2.48-2.40 (m, 2H), 1.52 (s, 9H)

Quelle