ORGANIC CHEMISTRY Chapter 5 5.8 The Origin of Optical Activity Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 5 5.8 The Origin of Optical Activity
ORGANIC CHEMISTRY Chapter 5 58 a Racemic form(外消旋体) g An equimolar mixture of two enantiomers is called a racemic form(either a racemate or a racemic mixture) o A racemic form shows no rotation of plane polarized light o It is often designated as being(+) CH CH 二 HO~c∠1+ H~二OH CH C CHOH HOcH CH2CH3 HOcH (R)-()-2-Butanol (S)-(+)-2-Butano (±)-2- Butanol 13.52 ab=+13.52 Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 5 5.8A Racemic Form (外消旋体) An equimolar mixture of two enantiomers is called a racemic form (either a racemate or a racemic mixture). A racemic form shows no rotation of planepolarized light. It is often designated as being (±). CH3 CHOH CH2CH3 (±)-2-Butanol [α]D25 = 0 C CH2CH3 CH3 HO H C CH2CH3 CH3 H OH (R)-(−)-2-Butanol (S)-(+)-2-Butanol [α]D25 = −13.52 [α]D25 = +13.52 + 1:1
ORGANIC CHEMISTRY Chapter 5 5.8b Racemic forms and enantiomeric Excess(外消旋体及对映体过量百分率) moles of one enantiomer-moles of other enantiomer 100% total moles of both enantiomers observed specific rotation 1009 specific rotation of the pure enantiomer R]_[S ×100% R]+[S] o ee= o enantiomeric excess Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 5 5.8B Racemic forms and Enantiomeric Excess (外消旋体及对映体过量百分率) moles of one enantiomer − moles of other enantiomer total moles of both enantiomers = observed specific rotation specific rotation of the pure enantiomer % ee = × 100% × 100% = [R]－[S] [R]＋[S] × 100% % ee = % enantiomeric excess
ORGANIC CHEMISTRY Chapter 5 5.9 The Synthesis of Chiral Molecules 手性分子的合成 Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 5 5.9 The Synthesis of Chiral Molecules 手性分子的合成
ORGANIC CHEMISTRY Chapter 5 5.9A Racemic forms OH Ch Cho CCh2 + h-h CH3CH2CHCH3(±) 2-butanone (±)-2- butanone (achiral achira Chiral molecules molecules) molecules but 50: 50 mixture()and(s)i Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 5 5.9A Racemic Forms CH3CH2CCH3 O + H H CH3CH2CHCH3 OH Ni (±) 2-butanone (±)-2-butanone (achiral molecules) (achiral molecules) [chiral molecules but 50:50 mixture (R) and (S)]