Reaktion #2174204

Reaktionsgleichung

14

1,2,5-tris-(t-Butyldimethylsilyloxy)-3-chlorobenzene

N-bromosuccinimide

DMF

→

bromide

Ausbeute 67.0%

5-Bromo-6-chloro-1,2,4-tris-(t-butyldimethylsilyloxy)benzene

Ausbeute 67.0%

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted three times with diethyl ether (50 Ml each), and the combined extracts
2. 2
   Waschenwere washed with 30 Ml of water, and 30 Ml of brine
3. 3
   Trocknendried (MgSO4)
4. 4
   Einengenconcentrated
5. 5
   Sonstigecolumn chromatographed on silica gel using
6. 6
   workup.ADDITIONa gradient mixture of hexane and diethyl ether as eluent

Vorschrift

A mixture of 0.650 g (1.30 mmol) of 14 and 0.276 g (1.60 mmol) of N-bromosuccinimide (NBS) in 10 Ml of DMF under argon was stirred at 25° C. for 5 days. The reaction mixture was diluted with 30 Ml of water, extracted three times with diethyl ether (50 Ml each), and the combined extracts were washed with 30 Ml of water, and 30 Ml of brine, dried (MgSO4), concentrated, and column chromatographed on silica gel using a gradient mixture of hexane and diethyl ether as eluent gave 0.506 g (67% yield) of bromide 4. 1H NMR (CDCl3) δ 6.41 (s, 1H, Ar, C3-H), 1.03 (s, 9H, t-Bu), 1.02 (s, 9H, t-Bu), 0.97 (s, 9H, t-Bu), 0.23 (s, 6H, Me), 0.22 (s, 6H, Me), 0.18 (s, 6H, Me); 13C NMR (CDCl3) δ 147.3 (s), 147.2 (s), 139.4 (s), 128.3 (s), 111.1 (d), 108.4 (s), 29.9 (q, t-Bu), 26.3 (q, t-Bu), 26.2 (q), 26, 18.9 (s), 18.6 (s), −3.3 (q, Me), −3.4 (q, Me), −3.5 (q, Me), −4.0 (q). Anal. Calcd for C24H46BrClO3Si3: C, 49.51; H, 7.96. Found: C, 49.78; H, 8.11.

Quelle