Reaktion #80410

Reaktionsgleichung

HCl

trimethyl borate

n-BuLi

2-fluoropyridine

→

2-fluoro-3-dihydroxyborylpyridine

Lösungsmittel

water THF

THF

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONare added in the course of 3 minutes
2. 2
   workup.ADDITIONis added at 25° C.
3. 3
   Temperaturcooling
4. 4
   SonstigeThe organic phase is separated off
5. 5
   Waschenthe aqueous phase is washed twice using Et2O
6. 6
   Filtrationfiltered
7. 7
   Einengenconcentrated in vacuo

Vorschrift

800 ml (1.28 mol) of n-BuLi (1.6M in hexane) are added to a solution of 188 ml (1.32 mol) of TMP in 1,000 ml of THF at -78° C. under argon. After the mixture has been stirred for 45 minutes at this temperature, 120.4 g (1.24 mol) of 2-fluoropyridine in 200 ml of THF are added in the course of 3 minutes. After the mixture has been stirred for 4 hours at -78° C., a solution of 128.8 g (1.24 mol) of trimethyl borate in 200 ml of THF is added dropwise in the course of 20 minutes. Then, 200 ml of a 1: 1 mixture of water/THF is added at 25° C., and 256 ml of concentrated HCl are added dropwise, with ice-cooling. The organic phase is separated off, and the aqueous phase is washed twice using Et2O, filtered and concentrated in vacuo. Crude yield 148.2 g.

Quelle