Question

4. (A.) Explain why something resembling SN2 reaction can occur at tertiary carbons of epoxides. We've previously noted that the energy of activation is too high for SN2 reactions at tertiary carbons. You did see SN2 reaction at tertiary silicon (TMS protecting group) in chapter 12. (B.) Explain why substitution at a tertiary carbon of an epoxide is favored over primary or secondary carbons under acid-catalyzed conditions. 5. In the accepted mechanism for oxidation of a thiol to a disulfide using Br2 and a base, there is a step that is very similar to a step in the oxidation of an alcohol to carbonyl using Cr(VI) reagents (the one where a heteroatom loses a pair of electrons to the oxidant). Describe the similarity. I'm just trying various ways to trigger you to put together the bigger picture so that future concepts "sink in" more easily.

          4. (A.) Explain why something resembling SN2 reaction can occur at tertiary carbons of epoxides. We've previously noted that the energy of activation is too high for SN2 reactions at tertiary carbons. You did see SN2 reaction at tertiary silicon (TMS protecting group) in chapter 12. (B.) Explain why substitution at a tertiary carbon of an epoxide is favored over primary or secondary carbons under acid-catalyzed conditions.
5. In the accepted mechanism for oxidation of a thiol to a disulfide using Br2 and a base, there is a step that is very similar to a step in the oxidation of an alcohol to carbonyl using Cr(VI) reagents (the one where a heteroatom loses a pair of electrons to the oxidant). Describe the similarity. I'm just trying various ways to trigger you to put together the bigger picture so that future concepts "sink in" more easily.

4. (A.) Explain why something resembling SN2 reaction can occur at tertiary carbons of epoxides. We've previously noted that the energy of activation is too high for SN2 reactions at tertiary carbons. You did see SN2 reaction at tertiary silicon (TMS protecting group) in chapter 12. (B.) Explain why substitution at a tertiary carbon of an epoxide is favored over primary or secondary carbons under acid-catalyzed conditions.
5. In the accepted mechanism for oxidation of a thiol to a disulfide using Br2 and a base, there is a step that is very similar to a step in the oxidation of an alcohol to carbonyl using Cr(VI) reagents (the one where a heteroatom loses a pair of electrons to the oxidant). Describe the similarity. I'm just trying various ways to trigger you to put together the bigger picture so that future concepts "sink in" more easily.

Added by Amber G.

Question

Please give Ace some feedback