{"id":619,"date":"2015-08-11T15:15:40","date_gmt":"2015-08-11T15:15:40","guid":{"rendered":"http:\/\/www.studyorgo.com\/blog\/?p=619"},"modified":"2015-08-11T15:15:40","modified_gmt":"2015-08-11T15:15:40","slug":"chirality-and-assigning-stereochemistry-to-molecules","status":"publish","type":"post","link":"https:\/\/www.studyorgo.com\/blog\/chirality-and-assigning-stereochemistry-to-molecules\/","title":{"rendered":"Chirality and Assigning Stereochemistry to Molecules"},"content":{"rendered":"

One of the most important skills to master in organic chemistry is the ability to assign stereochemistry.\u00a0 We at StudyOrgo have devised clear cut explanations of these difficult concepts for students to maximize their time studying and learn difficult concepts quickly and easily. Sign up with StudyOrgo.com today for all of your organic chemistry studying needs!<\/p>\n

Chirality is an important aspect of life.\u00a0 This is so because many of the basic molecules used in living cells, in particular amino acids that form enzymes, are also chiral. Chirality imparts asymmetry on our molecules, allowing them the ability to recognize \u201chandedness\u201d and further add to the complexity and specificity of reactions. As organic chemists, we must pay constant attention to the chirality of molecules both before and after reactions, less the compounds lose their biological or chemical activity.<\/p>\n

Chirality<\/u><\/em><\/strong> is defined as any object in which the mirror images are not superimposable. A good example is your hands; they are mirror images but not superimposable. Translating this to organic molecules, a stereocenter<\/u><\/em><\/strong> is a carbon center with 4 unique substituents that are arranged such that the mirror image is not superimposable. Thus, they \u201clook\u201d like to different molecules although they have the same substituents. If we alter the arrangement of the substituents, we can always come up with 2 arrangements for each substituent, R or S configuration.\u00a0 Thus, each stereocenter must have 2 stereoisomers<\/em>.<\/p>\n

\"chiral<\/a><\/p>\n

In order to determine whether the sterecenter\u00a0is the the R or S configuration, there are a series of steps to follow.<\/p>\n

    \n
  1. Identify the stereocenter<\/strong> as 4 unique substituents attached to the chiral center<\/li>\n
  2. Assign priority<\/strong> based on atom atomic number, highest (1) to lowest (4) weight.<\/li>\n
  3. If two atoms are same, move to next bond to find first point of difference<\/li>\n
  4. Rotate the molecule<\/strong> so that Priority 4 atom is in the hashed wedge position.<\/li>\n
  5. Determine the Priority sequence<\/strong> 1-2-3 rotates to the left (S) or the right (R).<\/li>\n<\/ol>\n

    \"chiral<\/a><\/p>\n

    Lastly, an important concept to keep in mind is that as molecules become more complex, they also can acquire more stereocenters.\u00a0 Keeping in mind that each stereocenter can produce 2 stereoisomers, we describe possible stereoisomerism using the 2n<\/sup> rule. Let\u2019s examine a molecule with 2 stereocenters, following the 2n rule that gives us 22<\/sup>=4 stereocenters.\u00a0 The possible combinations are listed below.<\/p>\n

    \"Screen<\/a><\/p>\n

    We now introduce the last concept to stereochemistry which is the difference between enantiomers and diastereomers.\u00a0 Enantiomers<\/u><\/em><\/strong> are molecules with exactly opposite<\/strong> stereoisomers.\u00a0 For example, the enantiomer of the molecule with stereochemistry R,R would be S,S.\u00a0 The relationship between molecule R,R and R,S is what is described as diastereomers<\/u><\/em><\/strong>, which differ in some but not<\/strong> all stereocenters.<\/p>\n

    Let\u2019s consider the biologically active form of testosterone, 5-DHT which is shown below.\u00a0 We indicate that it has 7 stereocenters in the molecule.\u00a0 Applying the 2n rule, we calculate 128 possible stereoisomer combinations.\u00a0 That concludes that while testosterone has 1 enantiomer, it has 126 diastereomers and remember\u2026only 5-DHT\u00a0works on our bodies!<\/p>\n

    \"Screen<\/a><\/p>\n

     <\/p>\n","protected":false},"excerpt":{"rendered":"

    One of the most important skills to master in organic chemistry is the ability to assign stereochemistry.\u00a0 We at StudyOrgo have devised clear cut explanations of these difficult concepts for students to maximize their time studying and learn difficult concepts quickly and easily. Sign up with StudyOrgo.com today for all of your organic chemistry studying […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[1,12,13],"tags":[35,34,30,18,36,37],"class_list":["post-619","post","type-post","status-publish","format-standard","hentry","category-organic-chemistry","category-q-and-a","category-tips","tag-diastereomers","tag-enantiomers","tag-fall-semester","tag-organic","tag-stereochemistry","tag-stereoisomer"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/posts\/619","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/comments?post=619"}],"version-history":[{"count":1,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/posts\/619\/revisions"}],"predecessor-version":[{"id":622,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/posts\/619\/revisions\/622"}],"wp:attachment":[{"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/media?parent=619"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/categories?post=619"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/tags?post=619"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}