Question

sodium cyanide, NC 13. Which of the following reacts the slowest with sodium cyanide 13. What functional group is present in each of the following molecules? он 14. Define Zaitsev's Rule: This is an empirical rule for predicting the favored alkene product in elimination ron. 15. In the deuterium-labeled compound below dehydrohalogenation with sodium ethoxide in ethanol produced 3-methyl cyclohexene (No deuterium present). Give an explanation for this. H Br H3CD HH NaOCH2CH3 CH3CH OH H3C HE

Answer 1

13. Compound B react with NaCN slowly because OTs is leaving and carbocation formed is more sterically hindered than other carbocations and nucleophilic attack of cyanide is slow.

-OTS Sterically hinde red carbocation -OTS OTS Less sterically hindered carbocation

13. Functional group

OH Fun. group Ether Carboxylic acid Amide

14. Zaitsev's rule: Zaitsev's rule states that during elimination reaction more substituted product is more stable hence is more favoured.

y NaOH Nick Major product munor product

15. This is E2 elimination reaction, cyclohexane ring structure (A) indicated that methyl and deuterium groups are below facing and bromo is top facing. Draw structure in chair form (structure-B) indicate that CH3, D and Br are equtorial position. Eliminnation can only occur when leaving broup at axial, hence flip chair ring to bring bromo to axial position to get compound C. In compound C hydrogen at C3 is equatorial hence elimination will not occur while at C1 deuterium is anti to bromo will eliminate and C1 hydrogen is equtorial will not eliminate.

  

Br н flip ring HD H. CH3 Br-equetorial Br-axial C Antil elimination E2-elimination H3C