CHM 238 - Ch 4 McMurray - Chap 4 Cycloalkanes Cycloalkanes...

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

Chap 4 Cycloalkanes:
Image of page 1

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

Cycloalkanes: Molecular formula has two less hydrogens for each ring in structure. n 2n+2-2(#rings) 10 2(10)+2-2(2) 10 18 C H For example: 10 carbons & 2 rings C H C H = H 2 C H 2 C C H 2 CH CH H 2 C C H 2 CH 2 CH 2 H 2 C H 2 C H 2 C C H 2 CH H 2 C CH 2 CH 2 C H 2 H 2 C CH CH CH H 2 C H 2 C H 2 C H 2 C C H 2 C H 2 CH 2 H 2 C H 2 C H 2 C C H 2 C H 2 C H 2 C CH 2 CH 2 CH 2 H 2 C
Image of page 2
Naming Cycloalkanes: For an unsubstituted monocyclic structure, add the prefix cyclo- to the name of the normal alkane of the same number of carbons. cyclobutane cyclopentane cyclooctane
Image of page 3

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

Substituted Cycloalkanes: Monosubstituted cycloalkanes are easily named by prefixing the name of the substituent to the name of the cycloalkane. propylcyclobutane methylcyclopentane ethylcyclooctane CH 2 CH 3 CH 3
Image of page 4
Polysubstituted Cycloalkanes: 1. With two or more substituents on a ring, the carbons are numbered so that the substituents receive the lowest total of the locant numbers possible. H 3 C CH 3 CH 3 CH 3 1 2 3 4 5 6 1 1 2 4 1,1,2,4-tetramethylcyclohexane
Image of page 5

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

Cycloalkyl Groups: Substituents consisting of cycloalkyl groups are also relatively common. H 2 C H 2 C CH cyclopropyl group cyclohexyl group cyclopentyl group
Image of page 6
Restricted Rotations in Cycloalkanes: In most cycloalkanes there is some degree of rotational movement available, but not complete rotation about each of the single bonds. CompleteTwist Prevented by rest of ring.
Image of page 7

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

Geometric Isomers: Because of the restricted rotation, substituents on top cannot be rotated to replace groups on the bottom without exchanging all top and bottom groups. 180° rotation 180° rotation
Image of page 8
Geometric Isomers: The two 1,3- dimethylcyclo- pentanes on the right are different compounds with different physical properties. H 3 C CH 3 H H H CH 3 H H 3 C
Image of page 9

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

Geometric Relationships: Two groups on different carbons of a cycloalkane are said to be cis to each other if they are on the same face and trans to each other if they are on
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