{"id":578,"date":"2017-10-04T21:00:28","date_gmt":"2017-10-04T21:00:28","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/?post_type=chapter&#038;p=578"},"modified":"2018-10-03T17:29:00","modified_gmt":"2018-10-03T17:29:00","slug":"cyclohexane","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/chapter\/cyclohexane\/","title":{"raw":"Cyclohexane","rendered":"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>explain why cyclohexane rings are free of angular strain.<\/li>\r\n \t<li>draw the conventional shorthand structure of a cyclohexane ring.<\/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\nMake certain that you can define, and use in context, the key terms below.\r\n<ul>\r\n \t<li>chair conformation<\/li>\r\n \t<li>twist-boat conformation<\/li>\r\n<\/ul>\r\n<\/div>\r\nRings larger than cyclopentane would have angle strain if they were planar. However, this strain, together with the eclipsing strain inherent in a planar structure, can be relieved by puckering the ring. Cyclohexane is a good example of a carbocyclic system that virtually eliminates eclipsing and angle strain by adopting non-planar conformations. Cycloheptane and cyclooctane have greater strain than cyclohexane, in large part due to transannular crowding (steric hindrance by groups on opposite sides of the ring).\r\n\r\n<\/div>\r\n<div id=\"section_1\">\r\n<h4 class=\"editable\">Conformations of Cyclohexane<\/h4>\r\nA planar structure for cyclohexane is clearly improbable. The bond angles would necessarily be 120\u00ba, 10.5\u00ba larger than the ideal tetrahedral angle. Also, every carbon-carbon bond in such a structure would be eclipsed. The resulting angle and eclipsing strains would severely destabilize this structure. If two carbon atoms on opposite sides of the six-membered ring are lifted out of the plane of the ring, much of the angle strain can be eliminated.\r\n\r\n<img class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210018\/cyc6cnf.gif\" alt=\"image\" \/>\r\n\r\nThis boat structure still has two eclipsed bonds and severe steric crowding of two hydrogen atoms on the \"bow\" and \"stern\" of the boat. This steric crowding is often called steric hindrance. By twisting the boat conformation, the steric hindrance can be partially relieved, but the twist-boat conformer still retains some of the strains that characterize the boat conformer. Finally, by lifting one carbon above the ring plane and the other below the plane, a relatively strain-free 'chair' conformer is formed. This is the predominant structure adopted by molecules of cyclohexane.\r\n\r\n<\/div>\r\n<div id=\"section_2\">\r\n<div class=\"textbox exercises\">\r\n<h3>Exercise<\/h3>\r\n<div id=\"section_2\">\r\n<div id=\"s61691\">\r\n<div id=\"section_20\">\r\n<h3 id=\"Questions-61691\">Question<\/h3>\r\nConsider the conformations of cyclohexane, chair, boat, twist boat. Order them in increasing strain in the molecule.\r\n\r\n<\/div>\r\n<div id=\"section_21\">\r\n<h3 id=\"Solutions-61691\">Solutions<\/h3>\r\n[reveal-answer q=\"732032\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"732032\"]Chair &lt; Twist Boat &lt; Boat\u00a0 (most strain)[\/hidden-answer]\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<div id=\"section_3\"><\/div>\r\n<\/div>\r\n<\/div>\r\n<div id=\"section_3\">\r\n<h3 class=\"editable\">Contributors<\/h3>\r\n<ul>\r\n \t<li>Robert Bruner (<a class=\"external\" title=\"http:\/\/bbruner.org\" href=\"http:\/\/bbruner.org\" target=\"_blank\" rel=\"external nofollow noopener\">http:\/\/bbruner.org<\/a>)<\/li>\r\n<\/ul>\r\nWilliam Reusch, Professor Emeritus (<a class=\"external\" title=\"http:\/\/www.msu.edu\/\" href=\"http:\/\/www.msu.edu\/\" target=\"_blank\" rel=\"external nofollow noopener\">Michigan State U.<\/a>), <a class=\"external\" title=\"http:\/\/www.cem.msu.edu\/~reusch\/VirtualText\/intro1.htm\" href=\"http:\/\/www.cem.msu.edu\/%7Ereusch\/VirtualText\/intro1.htm\" target=\"_blank\" rel=\"external nofollow noopener\">Virtual Textbook of\u00a0Organic\u00a0Chemistry<\/a>\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>explain why cyclohexane rings are free of angular strain.<\/li>\n<li>draw the conventional shorthand structure of a cyclohexane ring.<\/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<p>Make certain that you can define, and use in context, the key terms below.<\/p>\n<ul>\n<li>chair conformation<\/li>\n<li>twist-boat conformation<\/li>\n<\/ul>\n<\/div>\n<p>Rings larger than cyclopentane would have angle strain if they were planar. However, this strain, together with the eclipsing strain inherent in a planar structure, can be relieved by puckering the ring. Cyclohexane is a good example of a carbocyclic system that virtually eliminates eclipsing and angle strain by adopting non-planar conformations. Cycloheptane and cyclooctane have greater strain than cyclohexane, in large part due to transannular crowding (steric hindrance by groups on opposite sides of the ring).<\/p>\n<\/div>\n<div id=\"section_1\">\n<h4 class=\"editable\">Conformations of Cyclohexane<\/h4>\n<p>A planar structure for cyclohexane is clearly improbable. The bond angles would necessarily be 120\u00ba, 10.5\u00ba larger than the ideal tetrahedral angle. Also, every carbon-carbon bond in such a structure would be eclipsed. The resulting angle and eclipsing strains would severely destabilize this structure. If two carbon atoms on opposite sides of the six-membered ring are lifted out of the plane of the ring, much of the angle strain can be eliminated.<\/p>\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1518\/2017\/10\/04210018\/cyc6cnf.gif\" alt=\"image\" \/><\/p>\n<p>This boat structure still has two eclipsed bonds and severe steric crowding of two hydrogen atoms on the &#8220;bow&#8221; and &#8220;stern&#8221; of the boat. This steric crowding is often called steric hindrance. By twisting the boat conformation, the steric hindrance can be partially relieved, but the twist-boat conformer still retains some of the strains that characterize the boat conformer. Finally, by lifting one carbon above the ring plane and the other below the plane, a relatively strain-free &#8216;chair&#8217; conformer is formed. This is the predominant structure adopted by molecules of cyclohexane.<\/p>\n<\/div>\n<div id=\"section_2\">\n<div class=\"textbox exercises\">\n<h3>Exercise<\/h3>\n<div id=\"section_2\">\n<div id=\"s61691\">\n<div id=\"section_20\">\n<h3 id=\"Questions-61691\">Question<\/h3>\n<p>Consider the conformations of cyclohexane, chair, boat, twist boat. Order them in increasing strain in the molecule.<\/p>\n<\/div>\n<div id=\"section_21\">\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=\"q732032\">Show Answer<\/span><\/p>\n<div id=\"q732032\" class=\"hidden-answer\" style=\"display: none\">Chair &lt; Twist Boat &lt; Boat\u00a0 (most strain)<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<div id=\"section_3\"><\/div>\n<\/div>\n<\/div>\n<div id=\"section_3\">\n<h3 class=\"editable\">Contributors<\/h3>\n<ul>\n<li>Robert Bruner (<a class=\"external\" title=\"http:\/\/bbruner.org\" href=\"http:\/\/bbruner.org\" target=\"_blank\" rel=\"external nofollow noopener\">http:\/\/bbruner.org<\/a>)<\/li>\n<\/ul>\n<p>William Reusch, Professor Emeritus (<a class=\"external\" title=\"http:\/\/www.msu.edu\/\" href=\"http:\/\/www.msu.edu\/\" target=\"_blank\" rel=\"external nofollow noopener\">Michigan State U.<\/a>), <a class=\"external\" title=\"http:\/\/www.cem.msu.edu\/~reusch\/VirtualText\/intro1.htm\" href=\"http:\/\/www.cem.msu.edu\/%7Ereusch\/VirtualText\/intro1.htm\" target=\"_blank\" rel=\"external nofollow noopener\">Virtual Textbook of\u00a0Organic\u00a0Chemistry<\/a><\/p>\n<\/div>\n<\/div>\n","protected":false},"author":311,"menu_order":12,"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-578","chapter","type-chapter","status-publish","hentry"],"part":21,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/pressbooks\/v2\/chapters\/578","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\/578\/revisions"}],"predecessor-version":[{"id":2248,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/pressbooks\/v2\/chapters\/578\/revisions\/2248"}],"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\/578\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/wp\/v2\/media?parent=578"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/pressbooks\/v2\/chapter-type?post=578"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/wp\/v2\/contributor?post=578"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-organicchemistry\/wp-json\/wp\/v2\/license?post=578"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}