{"id":590,"date":"2017-10-04T21:01:45","date_gmt":"2017-10-04T21:01:45","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/?post_type=chapter&#038;p=590"},"modified":"2018-10-03T17:31:10","modified_gmt":"2018-10-03T17:31:10","slug":"axial-and-equatiorial-bonds-in-cyclohexane","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/chapter\/axial-and-equatiorial-bonds-in-cyclohexane\/","title":{"raw":"Axial and Equatiorial Bonds in Cyclohexane","rendered":"Axial and Equatiorial Bonds in Cyclohexane"},"content":{"raw":"<div class=\"elm-header\">\r\n<div class=\"elm-header-custom\">\r\n<div class=\"textbox learning-objectives\">\r\n<h3>Objectives<\/h3>\r\n<div id=\"elm-main-content\" class=\"elm-content-container\">\r\n<div>\r\n<div id=\"skills\">\r\n\r\nAfter completing this section, you should be able to\r\n<ol>\r\n \t<li>sketch the shorthand structure of cyclohexane, with axial and equatorial hydrogen atoms clearly shown and identified.<\/li>\r\n \t<li>identify the axial and equatorial hydrogens in a given sketch of the cyclohexane molecule.<\/li>\r\n \t<li>explain how chair conformations of cyclohexane and its derivatives can interconvert through the process of ring flip.<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<div id=\"elm-main-content\" class=\"elm-content-container\">\r\n<div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Key Terms<\/h3>\r\n<div>\r\n\r\nMake certain that you can define, and use in context, the key terms below.\r\n<ul>\r\n \t<li>axial position<\/li>\r\n \t<li>equatorial position<\/li>\r\n \t<li>ring flip<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<p class=\"boxtitle\">On careful examination of a chair conformation of cyclohexane, we find that the twelve hydrogens are not structurally equivalent. Six of them are located about the periphery of the carbon ring, and are termed equatorial. The other six are oriented above and below the approximate plane of the ring (three in each location), and are termed axial because they are aligned parallel to the symmetry axis of the ring.<\/p>\r\n\r\n<\/div>\r\n<img class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210104\/image042.png\" alt=\"image042.png\" width=\"286px\" height=\"113px\" \/>\r\n\r\nIn the figure above, the equatorial hydrogens are colored blue, and the axial hydrogens are in bold. Since there are two equivalent chair conformations of cyclohexane in rapid equilibrium, all twelve hydrogens have 50% equatorial and 50% axial character. The figure below illustrates how to convert a molecular model of cyclohexane between two different chair conformations - this is something that you should practice with models.\u00a0 Notice that a 'ring flip' causes equatorial hydrogens to become axial, and vice-versa.\r\n\r\n<img class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210107\/image043.png\" alt=\"image043.png\" width=\"657px\" height=\"317px\" \/>\r\n<div id=\"section_2\">\r\n<div id=\"section_1\">\r\n<h3 class=\"editable\">How to draw stereo bonds (\"up\" and \"down\" bonds)<\/h3>\r\n<div class=\"editIcon\"><\/div>\r\nThere are various ways to show these orientations. The solid (dark) \"up wedge\" I used is certainly common. Some people use an analogous \"down wedge\", which is light, to indicate a down bond; unfortunately, there is no agreement as to which way the wedge should point, and you are left relying on the lightness of the wedge to know it is \"down\". The \"down bond\" avoids this wedge ambiguity, and just uses some kind of light line. The down bond I used (e.g., in <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig5\" href=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig5\" target=\"_blank\" rel=\"external nofollow noopener\"> Figure 5B<\/a>) is a dashed line; IUPAC encourages a series of parallel lines, something like <img src=\"http:\/\/bbruner.org\/obc\/ring_fig\/downdash.gif#fixme\" alt=\"A down bond of the type IUPAC prefers. It is a series of parallel lines.\" width=\"35\" height=\"19\" \/>. What I did is a variation of what is recommended by IUPAC: <a class=\"external\" title=\"http:\/\/www.chem.qmul.ac.uk\/iupac\/stereo\/intro.html\" href=\"http:\/\/www.chem.qmul.ac.uk\/iupac\/stereo\/intro.html\" target=\"_blank\" rel=\"external nofollow noopener\"> http:\/\/www.chem.qmul.ac.uk\/iupac\/stereo\/intro.html<\/a>.\r\n<blockquote>In <strong> ISIS\/Draw<\/strong>, the \"up wedge\" and \"down bond\" that I used, along with other variations, are available from a tool button that may be labeled with any of them, depending on most recent use. It is located directly below the tool button for ordinary C-C bonds.\r\n\r\nIn <strong> Symyx Draw<\/strong>, the \"up wedge\" and \"down bond\", along with other variations, are available from a tool button that may be labeled with any of them, depending on most recent use. It is located directly below the \"Chain\" tool button.\r\n\r\n<strong>ChemSketch<\/strong> provides up and down wedges, but not the simple up and down bonds discussed above. The wedges are available from the second toolbar across the top. For an expanded discussion of using these wedges, see the section of my ChemSketch Guide on <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/chemsket.htm#Wedge\" href=\"http:\/\/bbruner.org\/obc\/chemsket.htm#Wedge\" target=\"_blank\" rel=\"external nofollow noopener\"> Stereochemistry: Wedge bonds<\/a>.\r\n\r\nAs always, the information provided on these pages in intended to help you get started. Each program has more options for drawing bonds than discussed here. When you feel the need, look around!<\/blockquote>\r\n<\/div>\r\n<\/div>\r\n<div id=\"section_3\">\r\n<div>\r\n<h3 class=\"editable\">How to Draw chairs<\/h3>\r\nMost of the structures shown on this page were drawn with the free program <strong> ISIS\/Draw<\/strong>. I have posted a guide to help you get started with <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/isis.htm\" href=\"http:\/\/bbruner.org\/obc\/isis.htm\" target=\"_blank\" rel=\"external nofollow noopener\"> ISIS\/Draw<\/a>. ISIS\/Draw provides a simple cyclohexane (6-ring) hexagon template on the toolbar across the top. It provides templates for various 6-ring chair structures from the Templates menu; choose Rings. There are templates for simple chairs, without substituents (e.g., <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig1\" href=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig1\" target=\"_blank\" rel=\"external nofollow noopener\"> Fig 1B<\/a>), and for chairs showing all the substituents (e.g., <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig2\" href=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig2\" target=\"_blank\" rel=\"external nofollow noopener\"> Fig 2B<\/a>). In either case, you can add, delete, or change things as you wish. Various kinds of stereo bonds (wedges and bars) are available by clicking the left-side tool button that is just below the regular C-C single bond button. It may have a wedge shown on it, but this will vary depending on how it has been used. To choose a type of stereo bond, click on the button and hold the mouse click; a new menu will appear to the right of the button.\r\n\r\nThe free drawing program <strong> Symyx Draw<\/strong>, the successor to ISIS\/Draw, provides similar templates and tools. A basic chair structure is provided on the default template bar that is shown. More options are available by choosing the Rings template. See my page <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/symyx.htm\" href=\"http:\/\/bbruner.org\/obc\/symyx.htm\" target=\"_blank\" rel=\"external nofollow noopener\"> Symyx Draw<\/a> for a general guide for getting started with this program.\r\n\r\nThe free drawing program <strong> ChemSketch <\/strong> provides similar templates and tools. To find the special templates for chairs, go to the <strong> Templates <\/strong> menu, choose <strong> Template Window<\/strong>, and then choose \"Rings\" from the drop-down menu near upper left. See my page <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/chemsket.htm\" href=\"http:\/\/bbruner.org\/obc\/chemsket.htm\" target=\"_blank\" rel=\"external nofollow noopener\"> ChemSketch<\/a> for a general guide for getting started with this program.\r\n\r\nIf you want to draw chair structures by hand (and if you are going on in organic chemistry, you should)... Be careful. The precise zigs and zags, and the angles of substituents are all important. Your textbook may offer you some hints for how to draw chairs. A short item in the Journal of Chemical Education offers a nice trick, showing how the chair can be thought of as consisting of an M and a W. The article is V Dragojlovic, A method for drawing the cyclohexane ring and its substituents. J Chem Educ 78:923, 7\/01. (I thank M Farooq Wahab, Chemistry, Univ Karachi, for suggesting that this article be noted here.)\r\n\r\nAside from drawing the basic chair, the key points in adding substituents are:\r\n<ul>\r\n \t<li>Axial groups alternate up and down, and are shown \"vertical\".<\/li>\r\n \t<li>Equatorial groups are approximately horizontal, but actually somewhat distorted from that, so that the angle from the axial group is a bit more than a right angle -- reflecting the common 109 degree bond angle.<\/li>\r\n \t<li>As cautioned before, it is usually easier to draw and see what is happening at the four corners of the chair than at the two middle positions. Try to use the corners as much as possible.<\/li>\r\n<\/ul>\r\n&nbsp;\r\n\r\nBecause axial bonds are parallel to each other, substituents larger than hydrogen generally suffer greater steric crowding when they are oriented axial rather than equatorial. Consequently, <strong><em>substituted cyclohexanes will preferentially adopt conformations in which the larger substituents assume equatorial orientation<\/em><\/strong>.\r\n\r\n<img class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210116\/image045.png\" alt=\"image045.png\" width=\"474px\" height=\"140px\" \/>\r\n\r\nWhen the methyl group in the structure above occupies an axial position it suffers steric crowding by the two axial hydrogens located on the same side of the ring.\r\n\r\n<img class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210118\/image048.png\" alt=\"image048.png\" width=\"188px\" height=\"183px\" \/>\r\n\r\nThe conformation in which the methyl group is equatorial is more stable, and thus the equilibrium lies in this direction\r\n\r\n<\/div>\r\n<\/div>\r\n<div>\r\n<div class=\"textbox exercises\">\r\n<h3>Exercises<\/h3>\r\n<div>\r\n<div id=\"s61691\">\r\n<div id=\"section_24\">\r\n<h3 id=\"Questions-61691\">Questions<\/h3>\r\n<strong>1.<\/strong>\r\n\r\nDraw two conformations of cyclohexyl amine (C<sub>6<\/sub>H<sub>11<\/sub>NH<sub>2<\/sub>). Indicate axial and equatorial positions.\r\n\r\n<b>2.<\/b>\r\n\r\nDraw the two isomers of 1,4-dihydroxylcyclohexane, identify which are equatorial and axial.\r\n\r\n<b>3.<\/b>\r\n\r\nIn the following molecule, label which are equatorial and which are axial, then draw the chair flip (showing labels 1,2,3).\r\n\r\n<img class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210120\/4-6-3qu.png\" alt=\"\" width=\"221\" height=\"154\" \/>\r\n\r\n<\/div>\r\n<div id=\"section_25\">\r\n<h3 id=\"Solutions-61691\">Solutions<\/h3>\r\n[reveal-answer q=\"30511\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"30511\"]\r\n\r\n<strong>1.<\/strong>\r\n\r\n<img class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210122\/4.6-1.png\" alt=\"\" width=\"500px\" height=\"211px\" \/>\r\n\r\n<strong>2.<\/strong>\r\n\r\n<img class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210124\/4.6-2.png\" alt=\"\" width=\"516px\" height=\"218px\" \/>\r\n\r\n<strong>3.\u00a0<\/strong>\r\n\r\n<img class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210126\/4-6-3sol.png\" alt=\"\" width=\"226\" height=\"147\" \/>[\/hidden-answer]\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<div id=\"section_4\">\r\n<h3 class=\"editable\">Contributors<\/h3>\r\n<ul>\r\n \t<li><a class=\"external\" title=\"http:\/\/science.athabascau.ca\/staff-pages\/dietmark\" href=\"http:\/\/science.athabascau.ca\/staff-pages\/dietmark\" target=\"_blank\" rel=\"external nofollow noopener\">Dr. Dietmar Kennepohl<\/a> FCIC (Professor of Chemistry, <a class=\"external\" title=\"http:\/\/www.athabascau.ca\/\" href=\"http:\/\/www.athabascau.ca\/\" target=\"_blank\" rel=\"external nofollow noopener\">Athabasca University<\/a>)<\/li>\r\n<\/ul>\r\nProf. Steven Farmer (<a class=\"external\" title=\"http:\/\/www.sonoma.edu\" href=\"http:\/\/www.sonoma.edu\" target=\"_blank\" rel=\"external nofollow noopener\">Sonoma State University<\/a>)\r\n\r\n<a title=\"Organic_Chemistry_With_a_Biological_Emphasis\" href=\"https:\/\/chem.libretexts.org\/Textbook_Maps\/Organic_Chemistry_Textbook_Maps\/Map%3A_Organic_Chemistry_with_a_Biological_Emphasis_(Soderberg)\" rel=\"internal\">Organic Chemistry With a Biological Emphasis <\/a>by\u00a0<a class=\"external\" title=\"http:\/\/facultypages.morris.umn.edu\/~soderbt\/\" href=\"http:\/\/facultypages.morris.umn.edu\/%7Esoderbt\/\" target=\"_blank\" rel=\"external nofollow noopener\">Tim Soderberg<\/a>\u00a0(University of Minnesota, Morris)\r\n\r\n<\/div>\r\n<\/div>","rendered":"<div class=\"elm-header\">\n<div class=\"elm-header-custom\">\n<div class=\"textbox learning-objectives\">\n<h3>Objectives<\/h3>\n<div id=\"elm-main-content\" class=\"elm-content-container\">\n<div>\n<div id=\"skills\">\n<p>After completing this section, you should be able to<\/p>\n<ol>\n<li>sketch the shorthand structure of cyclohexane, with axial and equatorial hydrogen atoms clearly shown and identified.<\/li>\n<li>identify the axial and equatorial hydrogens in a given sketch of the cyclohexane molecule.<\/li>\n<li>explain how chair conformations of cyclohexane and its derivatives can interconvert through the process of ring flip.<\/li>\n<\/ol>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<div id=\"elm-main-content\" class=\"elm-content-container\">\n<div>\n<div class=\"textbox key-takeaways\">\n<h3>Key Terms<\/h3>\n<div>\n<p>Make certain that you can define, and use in context, the key terms below.<\/p>\n<ul>\n<li>axial position<\/li>\n<li>equatorial position<\/li>\n<li>ring flip<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<p class=\"boxtitle\">On careful examination of a chair conformation of cyclohexane, we find that the twelve hydrogens are not structurally equivalent. Six of them are located about the periphery of the carbon ring, and are termed equatorial. The other six are oriented above and below the approximate plane of the ring (three in each location), and are termed axial because they are aligned parallel to the symmetry axis of the ring.<\/p>\n<\/div>\n<p><img decoding=\"async\" class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210104\/image042.png\" alt=\"image042.png\" width=\"286px\" height=\"113px\" \/><\/p>\n<p>In the figure above, the equatorial hydrogens are colored blue, and the axial hydrogens are in bold. Since there are two equivalent chair conformations of cyclohexane in rapid equilibrium, all twelve hydrogens have 50% equatorial and 50% axial character. The figure below illustrates how to convert a molecular model of cyclohexane between two different chair conformations &#8211; this is something that you should practice with models.\u00a0 Notice that a &#8216;ring flip&#8217; causes equatorial hydrogens to become axial, and vice-versa.<\/p>\n<p><img decoding=\"async\" class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210107\/image043.png\" alt=\"image043.png\" width=\"657px\" height=\"317px\" \/><\/p>\n<div id=\"section_2\">\n<div id=\"section_1\">\n<h3 class=\"editable\">How to draw stereo bonds (&#8220;up&#8221; and &#8220;down&#8221; bonds)<\/h3>\n<div class=\"editIcon\"><\/div>\n<p>There are various ways to show these orientations. The solid (dark) &#8220;up wedge&#8221; I used is certainly common. Some people use an analogous &#8220;down wedge&#8221;, which is light, to indicate a down bond; unfortunately, there is no agreement as to which way the wedge should point, and you are left relying on the lightness of the wedge to know it is &#8220;down&#8221;. The &#8220;down bond&#8221; avoids this wedge ambiguity, and just uses some kind of light line. The down bond I used (e.g., in <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig5\" href=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig5\" target=\"_blank\" rel=\"external nofollow noopener\"> Figure 5B<\/a>) is a dashed line; IUPAC encourages a series of parallel lines, something like <img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/bbruner.org\/obc\/ring_fig\/downdash.gif#fixme\" alt=\"A down bond of the type IUPAC prefers. It is a series of parallel lines.\" width=\"35\" height=\"19\" \/>. What I did is a variation of what is recommended by IUPAC: <a class=\"external\" title=\"http:\/\/www.chem.qmul.ac.uk\/iupac\/stereo\/intro.html\" href=\"http:\/\/www.chem.qmul.ac.uk\/iupac\/stereo\/intro.html\" target=\"_blank\" rel=\"external nofollow noopener\"> http:\/\/www.chem.qmul.ac.uk\/iupac\/stereo\/intro.html<\/a>.<\/p>\n<blockquote><p>In <strong> ISIS\/Draw<\/strong>, the &#8220;up wedge&#8221; and &#8220;down bond&#8221; that I used, along with other variations, are available from a tool button that may be labeled with any of them, depending on most recent use. It is located directly below the tool button for ordinary C-C bonds.<\/p>\n<p>In <strong> Symyx Draw<\/strong>, the &#8220;up wedge&#8221; and &#8220;down bond&#8221;, along with other variations, are available from a tool button that may be labeled with any of them, depending on most recent use. It is located directly below the &#8220;Chain&#8221; tool button.<\/p>\n<p><strong>ChemSketch<\/strong> provides up and down wedges, but not the simple up and down bonds discussed above. The wedges are available from the second toolbar across the top. For an expanded discussion of using these wedges, see the section of my ChemSketch Guide on <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/chemsket.htm#Wedge\" href=\"http:\/\/bbruner.org\/obc\/chemsket.htm#Wedge\" target=\"_blank\" rel=\"external nofollow noopener\"> Stereochemistry: Wedge bonds<\/a>.<\/p>\n<p>As always, the information provided on these pages in intended to help you get started. Each program has more options for drawing bonds than discussed here. When you feel the need, look around!<\/p><\/blockquote>\n<\/div>\n<\/div>\n<div id=\"section_3\">\n<div>\n<h3 class=\"editable\">How to Draw chairs<\/h3>\n<p>Most of the structures shown on this page were drawn with the free program <strong> ISIS\/Draw<\/strong>. I have posted a guide to help you get started with <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/isis.htm\" href=\"http:\/\/bbruner.org\/obc\/isis.htm\" target=\"_blank\" rel=\"external nofollow noopener\"> ISIS\/Draw<\/a>. ISIS\/Draw provides a simple cyclohexane (6-ring) hexagon template on the toolbar across the top. It provides templates for various 6-ring chair structures from the Templates menu; choose Rings. There are templates for simple chairs, without substituents (e.g., <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig1\" href=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig1\" target=\"_blank\" rel=\"external nofollow noopener\"> Fig 1B<\/a>), and for chairs showing all the substituents (e.g., <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig2\" href=\"http:\/\/bbruner.org\/obc\/rings.htm#Fig2\" target=\"_blank\" rel=\"external nofollow noopener\"> Fig 2B<\/a>). In either case, you can add, delete, or change things as you wish. Various kinds of stereo bonds (wedges and bars) are available by clicking the left-side tool button that is just below the regular C-C single bond button. It may have a wedge shown on it, but this will vary depending on how it has been used. To choose a type of stereo bond, click on the button and hold the mouse click; a new menu will appear to the right of the button.<\/p>\n<p>The free drawing program <strong> Symyx Draw<\/strong>, the successor to ISIS\/Draw, provides similar templates and tools. A basic chair structure is provided on the default template bar that is shown. More options are available by choosing the Rings template. See my page <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/symyx.htm\" href=\"http:\/\/bbruner.org\/obc\/symyx.htm\" target=\"_blank\" rel=\"external nofollow noopener\"> Symyx Draw<\/a> for a general guide for getting started with this program.<\/p>\n<p>The free drawing program <strong> ChemSketch <\/strong> provides similar templates and tools. To find the special templates for chairs, go to the <strong> Templates <\/strong> menu, choose <strong> Template Window<\/strong>, and then choose &#8220;Rings&#8221; from the drop-down menu near upper left. See my page <a class=\"external\" title=\"http:\/\/bbruner.org\/obc\/chemsket.htm\" href=\"http:\/\/bbruner.org\/obc\/chemsket.htm\" target=\"_blank\" rel=\"external nofollow noopener\"> ChemSketch<\/a> for a general guide for getting started with this program.<\/p>\n<p>If you want to draw chair structures by hand (and if you are going on in organic chemistry, you should)&#8230; Be careful. The precise zigs and zags, and the angles of substituents are all important. Your textbook may offer you some hints for how to draw chairs. A short item in the Journal of Chemical Education offers a nice trick, showing how the chair can be thought of as consisting of an M and a W. The article is V Dragojlovic, A method for drawing the cyclohexane ring and its substituents. J Chem Educ 78:923, 7\/01. (I thank M Farooq Wahab, Chemistry, Univ Karachi, for suggesting that this article be noted here.)<\/p>\n<p>Aside from drawing the basic chair, the key points in adding substituents are:<\/p>\n<ul>\n<li>Axial groups alternate up and down, and are shown &#8220;vertical&#8221;.<\/li>\n<li>Equatorial groups are approximately horizontal, but actually somewhat distorted from that, so that the angle from the axial group is a bit more than a right angle &#8212; reflecting the common 109 degree bond angle.<\/li>\n<li>As cautioned before, it is usually easier to draw and see what is happening at the four corners of the chair than at the two middle positions. Try to use the corners as much as possible.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p>Because axial bonds are parallel to each other, substituents larger than hydrogen generally suffer greater steric crowding when they are oriented axial rather than equatorial. Consequently, <strong><em>substituted cyclohexanes will preferentially adopt conformations in which the larger substituents assume equatorial orientation<\/em><\/strong>.<\/p>\n<p><img decoding=\"async\" class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210116\/image045.png\" alt=\"image045.png\" width=\"474px\" height=\"140px\" \/><\/p>\n<p>When the methyl group in the structure above occupies an axial position it suffers steric crowding by the two axial hydrogens located on the same side of the ring.<\/p>\n<p><img decoding=\"async\" class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210118\/image048.png\" alt=\"image048.png\" width=\"188px\" height=\"183px\" \/><\/p>\n<p>The conformation in which the methyl group is equatorial is more stable, and thus the equilibrium lies in this direction<\/p>\n<\/div>\n<\/div>\n<div>\n<div class=\"textbox exercises\">\n<h3>Exercises<\/h3>\n<div>\n<div id=\"s61691\">\n<div id=\"section_24\">\n<h3 id=\"Questions-61691\">Questions<\/h3>\n<p><strong>1.<\/strong><\/p>\n<p>Draw two conformations of cyclohexyl amine (C<sub>6<\/sub>H<sub>11<\/sub>NH<sub>2<\/sub>). Indicate axial and equatorial positions.<\/p>\n<p><b>2.<\/b><\/p>\n<p>Draw the two isomers of 1,4-dihydroxylcyclohexane, identify which are equatorial and axial.<\/p>\n<p><b>3.<\/b><\/p>\n<p>In the following molecule, label which are equatorial and which are axial, then draw the chair flip (showing labels 1,2,3).<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210120\/4-6-3qu.png\" alt=\"\" width=\"221\" height=\"154\" \/><\/p>\n<\/div>\n<div id=\"section_25\">\n<h3 id=\"Solutions-61691\">Solutions<\/h3>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q30511\">Show Answer<\/span><\/p>\n<div id=\"q30511\" class=\"hidden-answer\" style=\"display: none\">\n<p><strong>1.<\/strong><\/p>\n<p><img decoding=\"async\" class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210122\/4.6-1.png\" alt=\"\" width=\"500px\" height=\"211px\" \/><\/p>\n<p><strong>2.<\/strong><\/p>\n<p><img decoding=\"async\" class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210124\/4.6-2.png\" alt=\"\" width=\"516px\" height=\"218px\" \/><\/p>\n<p><strong>3.\u00a0<\/strong><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"internal default aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210126\/4-6-3sol.png\" alt=\"\" width=\"226\" height=\"147\" \/><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<div id=\"section_4\">\n<h3 class=\"editable\">Contributors<\/h3>\n<ul>\n<li><a class=\"external\" title=\"http:\/\/science.athabascau.ca\/staff-pages\/dietmark\" href=\"http:\/\/science.athabascau.ca\/staff-pages\/dietmark\" target=\"_blank\" rel=\"external nofollow noopener\">Dr. Dietmar Kennepohl<\/a> FCIC (Professor of Chemistry, <a class=\"external\" title=\"http:\/\/www.athabascau.ca\/\" href=\"http:\/\/www.athabascau.ca\/\" target=\"_blank\" rel=\"external nofollow noopener\">Athabasca University<\/a>)<\/li>\n<\/ul>\n<p>Prof. Steven Farmer (<a class=\"external\" title=\"http:\/\/www.sonoma.edu\" href=\"http:\/\/www.sonoma.edu\" target=\"_blank\" rel=\"external nofollow noopener\">Sonoma State University<\/a>)<\/p>\n<p><a title=\"Organic_Chemistry_With_a_Biological_Emphasis\" href=\"https:\/\/chem.libretexts.org\/Textbook_Maps\/Organic_Chemistry_Textbook_Maps\/Map%3A_Organic_Chemistry_with_a_Biological_Emphasis_(Soderberg)\" rel=\"internal\">Organic Chemistry With a Biological Emphasis <\/a>by\u00a0<a class=\"external\" title=\"http:\/\/facultypages.morris.umn.edu\/~soderbt\/\" href=\"http:\/\/facultypages.morris.umn.edu\/%7Esoderbt\/\" target=\"_blank\" rel=\"external nofollow noopener\">Tim Soderberg<\/a>\u00a0(University of Minnesota, Morris)<\/p>\n<\/div>\n<\/div>\n","protected":false},"author":311,"menu_order":13,"template":"","meta":{"_candela_citation":"[]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-590","chapter","type-chapter","status-publish","hentry"],"part":21,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/pressbooks\/v2\/chapters\/590","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/wp\/v2\/users\/311"}],"version-history":[{"count":5,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/pressbooks\/v2\/chapters\/590\/revisions"}],"predecessor-version":[{"id":2249,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/pressbooks\/v2\/chapters\/590\/revisions\/2249"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/pressbooks\/v2\/parts\/21"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/pressbooks\/v2\/chapters\/590\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/wp\/v2\/media?parent=590"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/pressbooks\/v2\/chapter-type?post=590"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/wp\/v2\/contributor?post=590"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/wp\/v2\/license?post=590"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}