Reaction #1747902

Reaction equation

PPh3

7-tert-butoxycarbonyl-2-[4-(2-hydroxyethyl)-2-methoxy-5-pyridinyl]-7-azabicyclo[2.2.1]hept-2-ene

CBr4

→

7-tert-butoxycarbonyl-2-[4-(2-bromoethyl)-2-methoxy-5-pyridinyl]-7-azabicyclo[2.2.1]hept-2-ene

Yield 87.0%

Solvents

CH2Cl2

CH2Cl2

Conditions

Workup

1. 1
   workup.STIRRINGAfter that the reaction mixture was stirred at room temperature for 2 h
2. 2
   Otherquenched by water
3. 3
   workup.ADDITIONdiluted with CH2Cl2
4. 4
   OtherThe organic layer was separated
5. 5
   Washwashed with brine
6. 6
   Dryingdried (Na2SO4)
7. 7
   Concentrationconcentrated
8. 8
   OtherThe residue was purified by chromatography with hexane/EtOAc (6:1)

Procedure

To a stirred solution of 7-tert-butoxycarbonyl-2-[4-(2-hydroxyethyl)-2-methoxy-5-pyridinyl]-7-azabicyclo[2.2.1]hept-2-ene (390 mg, 1.13 mmol) in dry CH2Cl2 (20 mL) under N2 was added CBr4 (745 mg, 2.25 mmol). The mixture was stirred at room temperature for 10 min, and then a solution of PPh3 (590 mg, 2.25 mmol) in dry CH2Cl2 (5 mL) was slowly added. After that the reaction mixture was stirred at room temperature for 2 h and quenched by water, and then diluted with CH2Cl2. The organic layer was separated and washed with brine, dried (Na2SO4), and concentrated. The residue was purified by chromatography with hexane/EtOAc (6:1) to afford 7-tert-butoxycarbonyl-2-[4-(2-bromoethyl)-2-methoxy-5-pyridinyl]-7-azabicyclo[2.2.1]hept-2-ene as a syrup (400 mg, 87%). 1H NMR (CDCl3) δ 7.95 (br s, 1H), 6.66 (s, 1H), 6.23 (br s, 1H), 4.86 (d, 1H, J=3.6 Hz), 4.81 (br s, 1H), 3.94 (s, 3H), 3.59-3.46 (m, 2H), 3.42-3.12 (m, 2H), 2.09-1.92 (m, 2H), 1.45 (s, 9H), 1.36-1.20 (m, 2H); 13C NMR (CDCl3) δ 163.83, 155.35, 148.55, 146.16, 144.63, 132.04, 123.16, 111.15, 80.16, 63.16, 61.35, 53.44, 35.97, 30.76, 28.20, 25.96 and 25.32, 24.55 and 23.62.

Source