In the synthesis of a pheromone outlined below, on which step the carbon skeleton is constructed...

 

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In the synthesis of a pheromone outlined below, on which step the carbon skeleton is constructed (a new carbon-carbon bond is formed)? НО HBr, C₂H 60-63% H₂, Lindlar, quinoline 75-85% HO Br =1/₂₂ 2 eq. n-BuLi Ac₂O, Py 90-95% D. Hydrogenation of the double bond E. Conversion of an alcohol to its ester НО Aco Scheme 42. A. Substitution of a hydroxy-group with Br B. Deprotonation of an alkyne with n-BuLi C. Substitution of Br with deprotonated alkyne 41 n=5 42n=7 43 n=9 34-46% overall yield; > 99% (Z) isomer above 22. In the synthesis from question connected with the double bond in the final product? A. The stating diol D. An alkyne B. n-BuLi E. AC₂0 what is the source of two carbons C. Lindlar catalyst 23. It was suggested, that the synthesis from question first can be improved by using 1-pentene instead of 1-pentyne, because it would make unnecessary the step of conversion of the carbon-carbon triple bond to the C=C bond. Please, critically think about this idea. What is your conclusion? A. It will not work, because on the last step, the alcohol will not react with AC₂0 B. It will work and produce a higher overall yield because of fewer steps C. It will not work, because 1-pentene is not acidic enough to produce a nucleophile necessary for alkylation D. It will work, but produce a lower yield E. It will not work, because on the step of nucleophilic substitution there is a bad leaving group In the synthesis of a pheromone outlined below, on which step the carbon skeleton is constructed (a new carbon-carbon bond is formed)? НО HBr, C₂H 60-63% H₂, Lindlar, quinoline 75-85% HO Br =1/₂₂ 2 eq. n-BuLi Ac₂O, Py 90-95% D. Hydrogenation of the double bond E. Conversion of an alcohol to its ester НО Aco Scheme 42. A. Substitution of a hydroxy-group with Br B. Deprotonation of an alkyne with n-BuLi C. Substitution of Br with deprotonated alkyne 41 n=5 42n=7 43 n=9 34-46% overall yield; > 99% (Z) isomer above 22. In the synthesis from question connected with the double bond in the final product? A. The stating diol D. An alkyne B. n-BuLi E. AC₂0 what is the source of two carbons C. Lindlar catalyst 23. It was suggested, that the synthesis from question first can be improved by using 1-pentene instead of 1-pentyne, because it would make unnecessary the step of conversion of the carbon-carbon triple bond to the C=C bond. Please, critically think about this idea. What is your conclusion? A. It will not work, because on the last step, the alcohol will not react with AC₂0 B. It will work and produce a higher overall yield because of fewer steps C. It will not work, because 1-pentene is not acidic enough to produce a nucleophile necessary for alkylation D. It will work, but produce a lower yield E. It will not work, because on the step of nucleophilic substitution there is a bad leaving group

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