8B_handout_feb18 - Chem 8B Handout for More Nucleophilic...

Info icon This preview shows pages 1–2. Sign up to view the full content.

Chem 8B, Handout for Feb 18, 2009, More Nucleophilic Acyl Substitution Reactions Sections 12.4-12.13 Fill in the following table comparing the reactivity (electrophilicity) of carbonyl compounds in nucleophilic acyl substitution reactions (based on the electronic effects and the stability of the leaving group. carbonyl how electrophilic? (ranking, where 1 = most electrophilic) electronic effects Leaving group (LG) conjugate acid of LG pKa of conjugate acid R Cl O R O O R OCH 3 O R OH O R N O CH 3 O R NH 2 O H CH 3 acid chloride anhydride ester carboxylic acid secondary amide primary amide ranking = 1 most electrophilic (no catalyst needed) inductive electron- withdrawing effects; No resonance ranking = 5 least electrophilic (need catalyst + heat) ranking = 4 not very electrophilic (need H + catalyst) ranking = 3 not very electrophilic (need H + catalyst) ranking = 2 good electrophilic (no catalyst needed) electron-donating effects from N; resonance stabilization R N O H CH 3 (Recall that the aldehyde and ketone do not have a leaving group, so they undergo addition reactions
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: instead of substitution reactions.) R Cl O + HO CH 3 R OCH 3 O substitution product electrophile nucleophile Nucleophilic Acyl Substitution reaction Nucleophiles = water, alcohols, amines, hydride (H: — ), and carbon anions (such as RLi and RMgBr) Acylation reactions for the synthesis of Aspirin TM Synthetic Option 1: (be able to draw a curved arrow mechanism for this reaction) OH OH O O OH O O H 3 C salicylic acid acetylsalicylic acid aspirin TM acetylation reaction + + Synthetic Option 2: OH OH O O OH O O H 3 C salicylic acid acetylsalicylic acid aspirin TM + + What are the advantages of synthetic option 1? What are the advantages of synthetic option 2? What structural features do aspirin and heroin have in common? O O H O N H (heroin) H 3 C O H 3 C O diacetylmorphine CH 3 O OH O O H 3 C acetylsalicylic acid aspirin TM...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern