Chapter 8 - Nucleophilic Substitution Chapter 8...

Info icon This preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Nucleophilic Substitution Chapter 8 Nucleophilic Substitution R = alkyl group X = leaving group Y = nucleophile Convenient means of functional group transformations R X transformed to R Y
Image of page 1

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

View Full Document Right Arrow Icon
Nucleophilic Substitution Nucleophilic substitution with alkyl halides is convenient means to prepare a variety of compounds Extremely useful reaction because alkyl halide are readily accessible: R-OH R 2 C=CR 2 Addition Nucleophilic Subst. R-X Alkyl halide Alcohol CHR 3 Alkane Alkenes Radical halogenation (e.g., X 2 + h ν ) (e.g., HX) (e.g., HX) R-Nu
Image of page 2
NaI is soluble in acetone; NaCl and NaBr are not soluble in acetone.
Image of page 3

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

View Full Document Right Arrow Icon
Nucleophilic Substitution Examples • When the substitution product bears a positive charge and also contains a proton bonded to O or N, the initially formed substitution product readily loses a proton to form a neutral product. Nucleophilic Substitution Examples
Image of page 4
Leaving Group • For example, H 2 O is a better leaving group than HO¯ because H 2 O is a weaker base. Leaving Group
Image of page 5

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

View Full Document Right Arrow Icon
Leaving Group Leaving Group
Image of page 6
A single organic product was obtained when 1-bromo-3-chloropropane was allowed to react with one molar equivalent of sodium cyanide in aqueous ethanol. What was this product? Problem 8.2 S N 2 Example
Image of page 7

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

View Full Document Right Arrow Icon
Stereochemistry of S N 2 Reactions Stereochemistry of S N 2 Reactions
Image of page 8
Steric Effects in S N 2 Reactions 221,000 1,350 1 Too small to measure Relative rates of S N 2 with Li I • Nucleophiles and bases are structurally similar • Both have a lone pair or a π bond. • They differ in what they attack. Nucleophiles vs. Bases
Image of page 9

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

View Full Document Right Arrow Icon
• Though nucleophilicity and basicity are interrelated, they are fundamentally different. Basicity is a measure of how readily an atom abstracts a proton. Characterized by an equilibrium constant ( K a ) in an acid-base reaction, making it a thermodynamic property . Nucleophiles vs. Bases Nucleophilicity is a measure of how fast an atom donates its electron pair to other atoms (usually carbon). Characterized by a rate constant, k , making it a kinetic property . It is generally true that a strong base is a strong nucleophile Nucleophilicity parallels basicity in three instances: 1. For two nucleophiles with the same nucleophilic atom and similar sterics, the stronger base is the stronger nucleophile . Example: HO¯ versus CH 3 COO¯ - Nucleophilicity determined by comparing p K a values of conjugate acids.
Image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the 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