1-(2',4'-Difluoro(1,1'-biphenyl)-4-yl)ethan-1-one → 3-(2',4'-Difluoro-4-biphenylyl)-2-butenoic acid

Beteiligte Stoffe

Reaktionsschritte

A solution of 21.4 g. of lithium diisopropylamide in 200 ml. of THF is added to a stirred solution of 32 g. of α-dibenzylphosphonoacetic acid (carboxymethylphosphonic acid dibenzyl ester) in 300 ml. of THF at -80°. Then a solution of 23.2 g. of 4-acetyl-2',4'-difluorobiphenyl in 250 ml. of THF is asdded. The mixture is stirred for 12 hours more, during which it is allowed to come to room temperature. The product Z--C(CH3)(OLi)--CH[P=O (OCH2C6H5)2 ]COOLi (Z is 2',4'-difluoro-4-biphenylyl), which is formed, is hydrolyzed with dilute acetic acid/ice. The customary work up gives 3-(2',4'-difluoro-4-biphenylyl)-2-butenoic acid, m.p. 193°-195°.

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