Reaktion #8694

Reaktionsgleichung

K3PO4

1-bromo-3,4-dimethyl-benzene

EA

→

2-(3,4-dimethyl-phenyl)-malonic acid dimethyl ester

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added under argon
2. 2
   TemperaturThe mixture was refluxed for 16 h
3. 3
   Filtrationfiltered
4. 4
   SonstigeThe filtrate was evaporated
5. 5
   Sonstigethe resulting brown oil was purified on silica gel eluting with heptane:EA 4:1 to 1:1

Vorschrift

(In analogy to a procedure given in J. Am. Chem. Soc. 122 (2000), 1360-1370.) To a suspension of Pd(OAc)2 (455 mg), 2-(di-tert.-butylphosphino)-biphenyl (1.21 g) and K3PO4 (39.6 g) in THF (200 ml) dimethylmalonate (12.85 g) and 1-bromo-3,4-dimethyl-benzene 15.0 g) was added under argon. The mixture was refluxed for 16 h, cooled to rt and diluted with EA (300 ml) and filtered. The filtrate was evaporated and the resulting brown oil was purified on silica gel eluting with heptane:EA 4:1 to 1:1 to give 2-(3,4-dimethyl-phenyl)-malonic acid dimethyl ester (16.2 g) as a colourless oil which slowly crystallises. 1H-NMR (300 MHz, CDCl3): 2.25(s, 3H), 2.26(s, 3H), 3.75(s, 6H), 4.59(s, 1H), 7.10–7.20(m, 3H).

Quelle