Chapter5 Stereochemistry(立体 化学): Chiral molecules(手性分 5.isomerism Constitutional isomers and stereoisomers (构形异构与立体异构)
Chapter 5 Stereochemistry（立体 化学）: Chiral Molecules（手性分 子） 5.1 Isomerism: Constitutional isomers and Stereoisomers (构形异构与立体异构）
Subdivison of isomers (Different compounds with same molecular formula) Constitutional isomers Stereoisomers (somers that have the same connectivity but that 1. CH3CH2CH-CH3( CH3)2CHCH3 differ in the arrangement of their atoms in space 2. CH3CHyCH2CI(CH3)2CHCI 3. CH3CH2OH CH3OCH Enantiomers(对映异构) Diastereomers(非立体 ( Stereoisomers that are mirror images of each other, 对映异构) but it is notsuperposa互为实物与镜象关系, (Stereoisomers that are not 但不重叠) mirror images of each ther)
Subdivison of isomers (Different compounds with same molecular formula) Constitutional isomers Stereoisomers (Isomers that have the same connectivity but that differ in the arrangement of their atoms in space 1. CH3CH2CH2CH3 (CH3 ) 2CHCH3 2. CH3CH2CH2Cl (CH3 ) 2CHCl 3. CH3CH2OH CH3OCH3 Enantiomers (对 映 异 构 ） Diastereomers (非 立 体 对 映 异 构 ) (Stereoisomers that are mirror images of each other, but it is notsuperposable 互 为 实 物 与 镜 象 关 系 ， 但 不 重 叠 ) (Stereoisomers that are not mirror images of each other)
Stereoisomers Isomers that have the same connectivity but that differ in the arrangement of their atoms in space Enantiomers(对映异构) Diastereomers(非立体对映异构 (Stereoisomers that are mirror images of each other, but it is notsuperposable互为实物与镜象关系,S Stereoisomers that are not mirror 但不重叠) images of each other) CH3 CH HILlII cH3cH∞x HO H3CH2C OH CH2CH3 H H CH H 2-butanol Cis trans
Stereoisomers (Isomers that have the same connectivity but that differ in the arrangement of their atoms in space Enantiomers (对 映 异 构 ） Diastereomers (非 立 体 对 映 异 构 ) (Stereoisomers that are mirror images of each other, but it is notsuperposable 互 为 实 物 与 镜 象 关 系 ， 但 不 重 叠 ) (Stereoisomers that are not mirror images of each other) CH3 H3CH2C OH H CH3 HO CH2CH3 H 2-butanol CH3 H CH3 H CH3 H H CH3 Cis - trans - H Cl H Cl H Cl Cl H
5.2 Enantiomers and chiral molecules a Chiral molecule is defined as one that is not superposable on its mirror image The chiral molecule and its mirror image are enantiomers, and the relationship between the chiral molecule and its mirror image is defined as enantiomeric(对映异构) The word chiral comes from the greek word Cheir, meaning hand. That means relationship between left hand and right hand
5.2 Enantiomers and chiral molecules • A Chiral molecule is defined as one that is not superposable on its mirror image. • The chiral molecule and its mirror image are enantiomers, and the relationship between the chiral molecule and its mirror image is defined as enantiomeric (对映异构）. • The word chiral comes from the Greek word Cheir, meaning ‘hand’. That means, relationship between left hand and right hand
52 Chiral molecules(手性分子) l( Chira)手性——物质分子与其镜象相似而不 重合的特征。 左手镜右手 Left hand〔左手)和 right hand(右手)相似而不重合
5.2 Chiral molecules (手性分子) • 1.(Chiral)手性——物质分子与其镜象相似而不 重合的特征。 Left hand (左手)和right hand(右手) 相似而不重合
CHa CH3 HH COOH Because models and ll are nonsuperposable mirror images of each other, the molecules that they represent are enantiomers
Because models I and II are nonsuperposable mirror images of each other, the molecules that they represent are enantiomers
Problem 5.1 Classify the following objects as to whether they are chiral(手性) or achiral ) Screw(舌onc Fork (d)Cup (e)Foot (t Ear (g) Shoe(h Spiral staircase(R 旋梯)
Problem 5.1 Classify the following objects as to whether they are chiral (手性） or achiral • (a) Screw （非手性） ( b) plain spoon (c ) Fork • (d) Cup (e) Foot (f) Ear • (g) Shoe (h) Spiral staircase（螺 旋梯）
Problem 5.2 (a)If models are available, construct the 2- butanols represented in Fig. 5.3 and demonstrate for yourself that they are not mutually superposable ( b) Make similar models of 2-propanol CH3CHOHCH3 ). Are they superposable? c)Is 2-propanol chiral? (d)Would you expect to find enantiomeric forms of 2-propanol?
Problem 5.2 • (a) If models are available, construct the 2- butanols represented in Fig. 5.3 and demonstrate for yourself that they are not mutually superposable. • (b) Make similar models of 2-propanol (CH3CHOHCH3 ). Are they superposable? • (c ) Is 2-propanol chiral? • (d) Would you expect to find enantiomeric forms of 2-propanol?
2-Butanol CH2CH3 CH2cH3 HCIIII 111ICH3 H○ OH (nonsuperposable) (chiraL) 2-Propanol CH3 CH3 H3CIIIII H○ OH (superposable) (achiraL
CH2 CH3 H H3 C HO CH2 CH3 H OH CH3 2-Butanol (nonsuperposable) (chiral) CH3 H H3 C HO CH3 H OH CH3 2-Propanol (superposable) (achiral)
one tetrahedral atom with four different groups attached to carbon it is ca| led chiral carbon(手性碳) a)CH3CHCICH3 (b )CH3CHBrCH2 CH3 C)CH3CHOHCHOHCH3()(CH3)2CHOH (e)BrCHCIl (f)CH3CH2CHCICH2CH3
one tetrahedral atom with four different groups attached to carbon, it is called chiral carbon（手性碳） • (a) CH3CHClCH3 (b) CH3CHBrCH2CH3 • (c ) CH3CHOHCHOHCH3 (d) (CH3 )2CHOH • (e) BrCHClI • (f) CH3CH2CHClCH2CH3