10-02 - Stereochemistry (Ch. 5) Please make a...

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Unformatted text preview: Stereochemistry (Ch. 5) Please make a methyl-decalin-ol molecule (with hydrogens) while you wait Keep a few extra carbons, oxygens and chlorines chlorines handy H H HO Stereochemistry O H The 2D molecular structure given for androsterone is ambiguous in 3D. androsterone a steroid Look at your methyl-decalin-ol model. 1 How many connection decisions are there? 2 Stereochemistry * = atom with 4 different groups H O Stereochemistry * = atom with 4 different groups H O * HO * * * * H* H * How many atoms have 4 different groups? a) 1 b) 3 c) 5 d) 6 f) 7 g) 8 h) 9 i) 10 3 * HO * * * * H* H * How How many isomers are represented by the ambiguous androsterone androsterone structure? a) 7 b) 14 c) 28 d) 56 e) 128 f) 256 g) 512 androsterone a steroid androsterone a steroid * = atoms where inversion of configuration gives a different structure. * = atoms where inversion of configuration gives a different structure. 27 = 128 4 Stereochemistry * = atom with 4 different groups H O Stereochemistry O H H HO HO H * HO * * * * H* H * How many isomers are represented by the ambiguous androsterone structure? H androsterone a steroid * = atoms where inversion of configuration gives a different structure. This molecular structure represents 128 different compounds! 5 This molecular molecular structure represents only one compound. compound. 6 27 = 128 1 Stereochemistry O H H HO H O H H HO H H HO 7 Stereochemistry O H H HO H H H O H These two compounds differ differ only in the orientation of bonds in space. They are called H H H stereoisomers. 8 Isomers Constitutional isomers have the same formula but different bond connectivity Covalent bonds must be broken to interconvert constitutional isomers. HH Isomers Constitutional isomers have the same formula but different bond connectivity Covalent bonds must be broken to interconvert constitutional isomers. HH H OH 9 ? H OH HH ? H OH HH H OH 3-heptanol 4-heptanol 3-heptanol 4-heptanol 4-heptanol 10 Isomers Isomers mirror mirror plane Stereoisomers have have the same formula and same formula the same bond same bond connectivity connectivity but the atoms are oriented differently in space. Covalent bonds Covalent bonds must be broken to interconvert constitutional constitutional and stereoisomers. stereoisomers. These molecules are identical. True or False? H OH HO H H OH 11 HO H 3-heptanol 3-heptanol 3-heptanol 3-heptanol 12 2 Isomers Stereoisomers have have the same formula and same formula the same bond same bond connectivity connectivity but the atoms are oriented differently in space. Covalent bonds Covalent bonds must be broken to interconvert constitutional constitutional and stereoisomers. stereoisomers. Isomers Stereoisomers have have the same formula and same formula the same bond same bond connectivity connectivity but the atoms are oriented differently in space. Covalent bonds Covalent bonds must be broken to interconvert constitutional constitutional and stereoisomers. stereoisomers. H OH HH HO OH 13 H OH HO H 3-heptanol 3-heptanol 14 Isomers (different structures with the same formula) Select Select the structures identical to A. Use a model !! = Cl H A constitutional isomers different structures with the same formula but different bond connectivities stereoisomers different structures with the same formula and the same bond connectivities 15 H Cl Cl Cl Cl 3 H Cl H Cl H 1 2 4 5 a) 1 & 3 e) 3 & 5 b) 1 & 5 b) f) 4 & 5 c) 2 & 4 c) g) 1 & 3 & 5 g) d) 3 & 4 d) 16 Select Select the structures identical to A. = Cl H Stereoisomers A Stereoisomers have the same formula and the same bond connectivity but their have same formula same bond their atoms are oriented differently in space. CH3 CH3 H H Cl Cl Cl Cl 3 H Cl H Cl H Recall Recall stereoisomerism of cycloalkanes substituted cycloalkanes & substituted alkenes (Ch. 4) lk (Ch H cis H CH3 H 1 2 4 5 CH3 a) 1 & 3 e) 3 & 5 b) 1 & 5 b) f) 4 & 5 c) 2 & 4 c) g) 1 & 3 & 5 g) d) 3 & 4 d) 17 trans 18 3 Stereoisomers CH3 H CH3 CH3 H H H CH3 CH3 Stereoisomers cis H CH3 H diastereomers Stereoisomers that are not mirror images. Cl Cl H H enantiomers Stereoisomers that are nonidentical mirror images 20 trans 19 Stereoisomers Stereoisomers enantiomers Stereoisomers that are nonidentical mirror images 21 enantiomers Stereoisomers that are nonidentical mirror images 22 Stereoisomers H CH3 CH3H3C H H CH3 H H Cl Cl H enantiomers Stereoisomers that are nonidentical mirror images 23 diastereomers enantiomers Stereoisomers Stereoisomers that are not mirror images. Stereoisomers that are nonidentical mirror images.24 4 Select Select the structures that are that enantiomers enantiomers of A Use a model !! H A Br Br H Br H Br diastereomers enantiomers Stereoisomers Stereoisomers that are not mirror images. Stereoisomers that are nonidentical mirror images.25 1 a) 1 & 2 e) e) 1 & 2 & 4 2 H 3 b) 1 & 3 b) f) 1 & 3 & 5 f) c) 2 & 4 c) g) 2 & 4 & 5 4 d) 3 & 4 d) h) 3 & 4 & 5 5 26 26 Select Select the structures that are that enantiomers enantiomers of A Use a model !! H Select Select the structures that are that enantiomers enantiomers of A Use a model !! H A Br A Br Br H Br H Br 1 a) 1 & 2 e) e) 1 & 2 & 4 2 b) 1 & 3 b) f) 1 & 3 & 5 f) 3 c) 2 & 4 c) g) 2 & 4 & 5 4 d) 3 & 4 d) h) 3 & 4 & 5 5 1 a) 1 & 2 e) e) 1 & 2 & 4 2 H 3 b) 1 & 3 b) f) 1 & 3 & 5 f) c) 2 & 4 c) g) 2 & 4 & 5 4 d) 3 & 4 d) h) 3 & 4 & 5 5 27 27 28 28 Select Select the structures that are that enantiomers enantiomers of A Use a model !! Stereoisomers H A Br 1 a) 1 & 2 e) e) 1 & 2 & 4 2 b) 1 & 3 b) f) 1 & 3 & 5 f) 3 c) 2 & 4 c) g) 2 & 4 & 5 4 d) 3 & 4 d) h) 3 & 4 & 5 5 Cl Cl H H Stereoisomers frequently have stereocenters (carbon atoms with four different substituents) 29 29 30 5 Stereoisomers Stereoisomers enantiomers Cl Cl H H Different Different compounds, must must have: different properties different names 31 b c enantiomers a d nomenclature 1. 1. rank the substituents on on stereocenter. stereocenter. (~ atomic number) 2. 2. orient molecule with lowest priority away from the 32 viewer. viewer. Stereoisomers Stereoisomers 3. 3. draw a curved arrow from the highest to the next next highest priority. b a d a d b b c a d c R c If If the arrow curves to the right(clockwise) the center of chirality is R. right(clockwise) is 2. 2. orient molecule with lowest priority away from the 33 viewer. viewer. If the If the arrow curves to the left (counterclockwise) the center of chirality is S. (counterclockwise) is 34 Stereoisomers The enantiomer/mirror The enantiomer/mirror image will have will the S designation. S R Stereoisomers Different compounds should have different names mirror If If the arrow curves to the right(clockwise) the center of chirality is R. right(clockwise) is If the If the arrow curves to the left (counterclockwise) the center of chirality is S. (counterclockwise) is 35 (S)-2-chlorobutane (R)-2-chlorobutane 36 6 What is the configuration? History of Chemistry Question Who was Knute Rockne? Cl H a) A chemist b) A football coach c) All of the above a) R b) S 37 d) None of the above 38 History of Chemistry Question Who was Knute Rockne? A chemist and a football coach (1888-1931) Why did the young, healthy Gipper die of a Strep infection? ? NH2 Dec 1, 1920 George Gipp George Gipp was his most famous player (1895-1920) 39 H N H S N Dec 14, 1920 HO O O O OH 40 Why did the young, healthy Gipper die of a Strep infection? ? We need yet another Dec 14, 1920 Dec generation of antibiotics 1, 1920 41 42 7 ...
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