Reaction #52971

Reaction equation

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

Yield 53.7%

Solvents

DME H2O

EtOAc

Conditions

Workup

1. 1
   Washwashed with water
2. 2
   Otherdried
3. 3
   Otherevaporated
4. 4
   workup.DISSOLUTIONThe residue was dissolved in EtOAc
5. 5
   Filtrationthe solution was filtered through a silica gel column
6. 6
   Otherevaporated
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
    Extractionextracted with EtOAc
11. 11
    WashThe extract was washed with water
12. 12
    Otherdried
13. 13
    Otherevaporated
14. 14
    OtherThe residue was purified by flash column chromatography (silica gel; eluent: EtOAc/hexane 1/2)

Procedure

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+).

Source