Note that the general formula for a cycloalkane composed of n carbons is CnH2n, and not CnH2n+2 as for alkanes. Cycloalkanes are very similar to the alkanes in reactivity, except for the very small ones, especially cyclopropane. CH3 A. Belmont, California: Thomson Higher Education, 2008. Organic Chemistry. Vollhardt, Schore. 3) When naming the cycloalkane, the substituents must be placed in alphabetical order. If there are two cycloalkanes in the molecule, use the cycloalkane with the higher number of carbons as the parent. Cyclohexane, one of the most common cycloalkanes is shown below as an example. There are also polycyclic alkanes, which are molecules that contain two or more cycloalkanes that are joined, forming multiple rings. The structural relationship of rings in a polycyclic compound can vary. Bruice, Paula Yurkanis. Give IUPAC names for the following compounds. (2-fluoro-1,1,-dimethylcyclohexane NOT 1,1-dimethyl-2-fluorocyclohexane). One way to make sure that the lowest number possible is assigned is to number the carbons so that when the numbers corresponding to the substituents are added, their sum is the lowest possible. draw all possible cycloalkane structures (substituted or unsubstituted) that correspond to a given molecular formula. Number the substituents of the ring so that the sum of the numbers is the lowest possible.
7th ed. a. a. b. Danvers, MA: Wiley, 2008. McMurry, John. Write an IUPAC name for the following alkane/cycloalkane: IUPAC Nomenclature IUPAC nomenclature is a system of assigning the name to the compounds, ions, elements or atoms that are globally excepted.
Molecules containing an alcohol group have an ending "-ol", indicating the presence of an alcohol group. The IUPAC names, molecular formulas, and skeleton structures of the first ten cycloalkanes are given in Table 4.1.1. 8) If the substituents of the cycloalkane are related by the cis or trans configuration, then indicate the configuration by placing "cis-" or "trans-" in front of the name of the structure. If there are two cycloalkanes, use the cycloalkane with the higher number of carbons as the parent chain. The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. More than one answer must be indicated for full credit. However, a cycloalkane with a triple bond-containing substituent is possible if the triple bond is not directly attached to the ring.
CH3 a. methyl v cyclobutane CH3 CH3 b. One way to make sure that the lowest number possible is assigned is to number the carbons so that when the numbers corresponding to the substituents are added, their sum is the lowest possible. Be sure to answer all parts. (Note: The structures are complex for practice purposes and may not be found in nature. The parent chain in this molecule is decane and cyclopropane is a substituent, . Provided that you have mastered the IUPAC system for naming alkanes, you should find that the nomenclature of cycloalkanes does not present any particular difficulties. Remember the prefixes di-, tri-, etc. H CH, CH, CH, -CH-CH, C C -CH=CH, CH2 CH2 СН. Cyclohexane, one of the most common cycloalkanes is shown below as an example. (Note: The structures are complex for practice purposes and may not be found in nature. 5th ed. & CA. Freeman, 2007. After completing this section, you should be able to. 9th ed. draw the Kekulé, shorthand or condensed structure for a substituted or unsubstituted cycloalkane, given its IUPAC name. Name the following structures. These compounds are known as cycloalkanes. Alcohol (-OH) substituents take the highest priority for carbon atom numbering in IUPAC nomenclature.
If you count the carbons and hydrogens, you will see that they no longer fit the general formula \(C_nH_{2n+2}\). Register now! The general formula of the cycloalkanes is \(C_nH_{2n}\) where \(n\) is the number of carbons. Organic Chemistry. Belmont, California: Thomson Higher Education, 2008. CH3 d. CH2CHCH CH3CHCH2CHCH2CH3 CH2CH2 2 (select) (select) (select) hexane After the carbon number and the dash, the name of the substituent can follow. All of the cycloalkanes, from cyclopentane upwards, exist as "puckered rings". ACD/ChemSketch Freeware, version 11.0, Advanced Chemistry Development, Inc., Toronto, ON, Canada, www.acdlabs.com, 2008. In general, for a hydrocarbon composed of n carbon atoms associated with m rings the formula is: CnH(2n + 2 - 2m). The longest straight chain contains 10 carbons, compared with cyclopropane, which only contains 3 carbons. © 2003-2020 Chegg Inc. All rights reserved. CH3 a. methyl v cyclobutane CH3 CH3 b. There must always be commas between the numbers and the dashes that are between the numbers and the names. After completing this section, you should be able to. Prentice Hall, 2006. (Note: The structures are complex for practice purposes and may not be found in nature. Numbering the location of the alcohol substituent is unnecessary because the ending "-ol" indicates the presence of one alcohol group on carbon atom number 1.
The smallest cycloalkane is cyclopropane. The carbon atom with the alcohol substituent must be labeled as 1. ), 7) 1,1-dibromo-3-butyl-5-fluoro-7-methylcyclooctane, 8) 1,1-dibromo-2,3-dichloro-4-propylcyclobutane, 9) 1-ethyl-2-methyl-1,3-dipropylcyclopentane, Blue=Carbon Yellow=Hydrogen Green=Chlorine, 1) cyclodecane 2) chlorocyclopentane or 1-chlorocyclopentane, 3) 3-cyclopropyl-6-methyldecane 4) cyclopentylcyclodecane or 1-cyclopentylcyclodecane 5) 1,3-dibromo-1-chloro-2-fluorocycloheptane, 10) cyclohexane 11) chlorocyclohexane 12) cyclopentylcyclohexane 13) 1-chloro-3-methylcyclobutane, Dr. Dietmar Kennepohl FCIC (Professor of Chemistry, Athabasca University), Prof. Steven Farmer (Sonoma State University), Organic Chemistry With a Biological Emphasis by Tim Soderberg (University of Minnesota, Morris). Classify each compound as an alkyl halide, a vinyl halide, or an aryl halide. The general formula for a cycloalkane is \(C_nH_{2n}\). 28. For more information contact us at info@libretexts.org or check out our status page at https://status.libretexts.org. Because cyclopropane is a substituent, it would be named a cyclopropyl-substituted alkane.