Under acidic conditions, there are no good nucleophiles present in solution, and the neutral epoxide is not sufficiently electrophilic for reaction with poor nucleophiles. Electrophilicity is enhanced by protonation. The cationic intermediate is attacked by water as a nucleophile. Draw the mechanistic step for protonation of an epoxide to generate a more electrophilic species H-OⓇ What is the regio- and stereoselectivity for the reaction shown below? What is the regio- and stereoselectivity for the reaction shown below? ⒸOAC Hg Which factor, steric accessibility or carbocation character, governs the attack of a nucleophile on a bridged carbocation? On that basis, what is the regio- and stereoselectivity for the reaction shown below? OH

Under acidic conditions, there are no good nucleophiles present in solution, and the neutral epoxide is not sufficiently electrophilic for reaction with poor nucleophiles. Electrophilicity is enhanced by protonation. The cationic intermediate is attacked by water as a nucleophile. Draw the mechanistic step for protonation of an epoxide to generate a more electrophilic species H-OⓇ What is the regio- and stereoselectivity for the reaction shown below? What is the regio- and stereoselectivity for the reaction shown below? ⒸOAC Hg Which factor, steric accessibility or carbocation character, governs the attack of a nucleophile on a bridged carbocation? On that basis, what is the regio- and stereoselectivity for the reaction shown below? OH

Organic Chemistry

8th Edition

ISBN:9781305580350

Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Publisher:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Chapter11: Ethers, Epoxides, And Sulfides

Section: Chapter Questions

Problem 11.18P

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