Reaktion #52971

Reaktionsgleichung

2,6-dimethoxy-4-(tert-butyl-diphenylsilyloxy)benzeneboronic acid

N-(2,6-dichlorobenzoyl)-4-bromo-L-phenylalanine ethyl ester

K2CO3

→

N-(2,6-dichlorobenzoyl)-4-(2,6-dimethoxy-4-hydroxyphenyl)-L-phenylalanine ethyl ester

Ausbeute 53.7%

Lösungsmittel

DME H2O

EtOAc

Reaktionsbedingungen

Aufarbeitung

1. 1
   Waschenwashed with water
2. 2
   Sonstigedried
3. 3
   Sonstigeevaporated
4. 4
   workup.DISSOLUTIONThe residue was dissolved in EtOAc
5. 5
   Filtrationthe solution was filtered through a silica gel column
6. 6
   Sonstigeevaporated
7. 7
   workup.DISSOLUTIONThe residue was dissolved in THF
8. 8
   workup.ADDITIONTBAF (1.6 M in THF, 4 ml) was added
9. 9
   workup.ADDITIONdiluted with water
10. 10
    Extraktionextracted with EtOAc
11. 11
    WaschenThe extract was washed with water
12. 12
    Sonstigedried
13. 13
    Sonstigeevaporated
14. 14
    SonstigeThe residue was purified by flash column chromatography (silica gel; eluent: EtOAc/hexane 1/2)

Vorschrift

A mixture of 2,6-dimethoxy-4-(tert-butyl-diphenylsilyloxy)benzeneboronic acid (3 g), N-(2,6-dichlorobenzoyl)-4-bromo-L-phenylalanine ethyl ester (0.8 g), Pd(PPh3)4 (1 g) and K2CO3 (2.1 g) in DME/H2O (20 mL/0.5 mL) was heated at 80° C. for 6 hour under N2. The mixture was diluted with EtOAc and washed with water, dried and evaporated. The residue was dissolved in EtOAc and the solution was filtered through a silica gel column and evaporated. The residue was dissolved in THF, and TBAF (1.6 M in THF, 4 ml) was added. The mixture was stirred at room temperature for 1 hour, diluted with water and extracted with EtOAc. The extract was washed with water, dried and evaporated. The residue was purified by flash column chromatography (silica gel; eluent: EtOAc/hexane 1/2) to yield 0.5 g of N-(2,6-dichlorobenzoyl)-4-(2,6-dimethoxy-4-hydroxyphenyl)-L-phenylalanine ethyl ester. ESMS m/z: 490 (MH+).

Quelle