Dicyclohexylcarbodiimide → (S)alpha-cyano-3-phenoxybenzyl(1R,cis)2,2-dimethyl-3-[2-(cyclopentyloxycarbonyl)ethynyl]-cyclopropane-carboxylate

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Reaktionsschritte

2.96 g of dicyclohexylcarbodiimide were added at 0° C. to a stirred mixture of 3.6 g of the product of Step B, 30 ml of methylene chloride and 30 mg of 4-dimethylaminopyridine followed by the addition of a solution of 3.3 g of (S)α-cyano-3-phenoxy-benzyl alcohol in 10 ml of methylene chloride. The mixture was stirred at 0° C. for 5 minutes and at 20°-25° C. for 3 hours and was filtered. The filtrate was evaporated to dryness under reduced pressure and the residue was chromatographed over silica gel. Elution with a cyclohexane-ethyl acetate mixture yielded 4.5 g of (S)α-cyano-3-phenoxybenzyl(1R,cis)2,2-dimethyl-3-[2-(cyclopentyloxycarbonyl)ethynyl]-cyclopropane-carboxylate with a melting point of =72° C.

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