反应详情

温度

-78 °C

0.1 mol of DCC, dissolved in methylene chloride, is added to a mixture of 0.1 mol of 4'-heptyloxy-2,3-difluorobiphenylcarboxylic acid (preparation: 0.1 mol of 2,3-difluoro-4'-heptyloxybiphenyl and 0.1 mol of TMEDA are dissolved in 200 ml of THF and the solution is cooled to -78° C. and reacted with 0.105 mol of a 1.6 N solution of Buli in hexane at this temperature. The reaction mixture is stirred at -78° C. for 3 hours and is then poured all at once onto 200 g of crushed dry ice. Customary working up gives 4'-heptyloxy-2,3-difluoro-biphenyl-4-carboxylic acid), 0.1 mol of optically active 2-cyano-2-methylhexan-1-ol (which can be prepared from optically active ethyl 2-methyl-2-butylcyanoacetate by reduction with LiBH4) and a catalytic amount of 4-N,N'-dimethylaminopyridine (DMAP) in 200 ml of methylene chloride at 0° C. The mixture is then stirred at room temperature for 12 hours. It is worked up in the customary manner and the product is purified by crystallization. Optically active 2-cyano-2-methylhexyl 4'-heptyloxy-2,3-difluorobiphenyl-4-carboxylate is obtained.

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