有机化学讲义-课件12.ppt

1、7、手性化合物的特性、手性化合物的特性旋光性旋光性2013-10-25HH3CHCH3HH3CHCH3H3CCH3H3CCH3cistransHHHHHHHHHHHHchiral molecules）：）：有手性现象的分子有手性现象的分子FBrClHFBrHClFBrClH手性分子手性分子镜像镜像CH3CHCHCH3Cl ClCH3CHCHCH2CH3Cl ClFCBrClHFCHClBr非非手性分子手性分子镜像镜像FClClHFClClHFClClHClBrClBrClBrClBrClBrClBr非非手性分子手性分子对映异构体对映异构体CH3HOHHOHCH3CH3HOHOHHCH3CH3O

2、HHHOHCH3IIIIIICH3HOHHHOCH3I对映关系对映关系CH3HOHHOHCH3IIICH3OHHHHOCH3IIICH3HOHHOHCH3IIICH3C2H5HOHCH3CC2H5OHHCH3C2H5OHH主链放在垂直方向上主链放在垂直方向上,伸向后方伸向后方CH3CC2H5OHHCH3HOHOHHCH3CH3OHHHOHCH3IIIC3 转180o23CH3HOHHOHCH323CH3OHHCH3HOH23CH3HOHCH3OHH23IIICH3OHHCH3HOH23I32将主链转至同一方向将主链转至同一方向互为镜像，不能重合互为镜像，不能重合2CH3HOHHOHCH3III

3、3CH3OHHCH3OHH23CH3HOHCH3OHH23IICH3OHHCH3HOH23IIIICH3OHHCH3OHH23CH3C2H5HOHH3CC2H5OHHCH3C2H5HOHCH3C2H5HOH交换CH3和C2H5I 的对映体交换CH3和OHH3CC2H5OHH交换 1 次交换 2 次交换 3 次H3CC2H5OHH交换H和C2H5III 的对映体CH3C2H5HOH以C H键为轴旋转60oCH3C2H5OHH以C CH3键为轴旋转60oCH3C2H5HOH以C OH键为轴旋转60oHH3CHOC2H5CHOCH2OHHOHCHOHOH2CHHO与与IIICHOCH2OHHOH交交

4、换换 1 1 次次H与OHCHOCH2OHHHO交交换换 2 2 次次H与 CHOOHCCH2OHHHO交交换换 3 3 次次CH2OH与 CHOCHOHOH2CHHOIII（接下页）（接下页）CH3HHOC2H5OHHOHCH3HHC2H5HO和和23III23交交换换 1 1 次次交交换换 2 2 次次 C2 CH3与与OHC2 CH3与与HCH3HHOC2H5OHH23IOHHH3CC2H5OHH23I 的的非非对对映映异异构构体体（接上页）（接上页）OHCH3HC2H5OHH23I交交换换 1 1 次次 C3 C2H5与与OHOHCH3HOHC2H5H23I 的的非非对对映映异异构构体

5、体交交换换 2 2 次次 C3 H 与与OHOHCH3HHC2H5HO23IOHCH3HHC2H5HOII23（C2、C3均均交换了偶数交换了偶数次）次）选择选择优先顺序优先顺序最小的原子或基团最小的原子或基团远离观察者，其余远离观察者，其余原子或基团依优先原子或基团依优先顺序排列顺序排列(S)2 丁醇丁醇(R)2 丁醇丁醇CH3C2H5HOHCH3C2H5OHHCH3CHC2H5OH*有一个手性碳有一个手性碳（1）如：如：I Br Cl S P F O N C D H（2）如：如：-CH2CH3 -CH3 -CH2Cl -CH2F -CH2OCH3 -CH2OH -CH(CH3)2 -CH2

6、CH(CH3)2BrClIHH 最小R 型CHCH2CHCH2CCCHOCHOOCCNCNNNCCCHOCH2OHHOHCHCH2OHHOHOCO123(R)-甘甘油油醛醛（构构型型？）甘甘油油醛醛CHCH2CHCH2CCCHCH2CH2CH2CH3与CHCH2CH3H与CCH3CH3CH3CCCCH3CH3CH3CH3HOHCH3OHH23IICH3OHHCH3HOH23IIIICH3OHHCH3OHH23CH3OHHCH3HOH23ICH3HOHH3COHH23CH3HOHH3COHH23CH3HOHCH3OHH23IICH3OHHCH3HOH23IIIICH3OHHCH3OHH23手性碳

7、与立体异构体数目的关系：手性碳与立体异构体数目的关系：若分子有若分子有 n 个手性碳，个手性碳，理论上理论上有有 2n 个立体异构体个立体异构体（2n/2对对 对映体。若手性碳组成相同，数目有所减少。对映体。若手性碳组成相同，数目有所减少。H3CCHCHCH3OHOHH3CCHCHC2H5OHOH*CH3HOHC2H5OHH23CH3OHHC2H5HOH23CH3OHHC2H5OHH23(2S,3S)-2,3-戊二醇(2R,3R)-2,3-戊二醇(2S,3R)-2,3-戊二醇CH3HOHC2H5HOH23(2R,3S)-2,3-戊二醇CH3OHHCH3OHHCH3OHHCH3ClHHFHClF

8、HClHHFHClFHClHHFHClFH180oCOOHHHOHHO23HOHCOOH4COOHHHOHOH23HOHCOOH4COOHHHOHHO23OHHCOOH4COOHHOHHOH23HOHCOOH4SRrSRsSSRRl连二烯型连二烯型（含有两个互相垂直的平面）（含有两个互相垂直的平面）CCCHClHClCCCHClHClCCCHClHHCCCHClHHCHCOOHHHOOCCHHOOCHCOOHNO2CO2HNO2CO2HNO2CO2HNO2CO2HHHHHHO2CCHCHOHCO2HOH*COOHHOHCOOHOHHCOOHOHHCOOHHOHCOOHOHHCOOHOHH(R,

9、R)-酒石酸酒石酸(S,S)-酒石酸酒石酸(R,S)-酒石酸酒石酸COOHHOHCOOHOHHCOOHOHHCOOHHOHCOOHOHHCOOHOHH熔点：比重（20o）水中溶解度pK1pK2171-174oC171-174oC146-148oC1.76g/cm31.76g/cm31.66g/cm3139g/100ml139g/100ml125g/100ml2.984.344.344.822.983.23相同相同a a 一对对映体对偏振光的作用不同，一个使偏振光向顺时一对对映体对偏振光的作用不同，一个使偏振光向顺时针方向偏转，另一个使偏振光向逆时针方向偏转，针方向偏转，另一个使偏振光向逆时针方

10、向偏转，两者偏转两者偏转数值相同数值相同。COOHHOHCOOHOHHCOOHOHHCOOHHOHa at =a a t l ca at :实验观察到的选光度实验观察到的选光度l:样品管长度（样品管长度（dm,分米）分米）c:样品浓度（样品浓度（g/cm3）t:测试时温度测试时温度:波长波长COOHOHHCOOHHOH例：例：Br2hv,CH3HBrC2H5CH3HBrC2H5+CH3CH2CH2CH350%50%外消旋体性外消旋体性(racemic mixture)CH3CHCH2CH3BrCOOHOHHCOOHOHH内消旋体表示方法内消旋体表示方法一个手性碳的旋光性正好一个手性碳的旋光性正

11、好被分子内另一构型相反的被分子内另一构型相反的手性碳所抵消手性碳所抵消内消旋体内消旋体(meso compounds)熔点：比重（20o）水中溶解度pK1pK2COOHHOHCOOHOHH171-174oC210-212oC146-148oC1.76g/cm31.70g/cm31.66g/cm3139g/100ml21g/100ml125g/100ml2.984.344.244.822.963.23COOHOHHCOOHHOH mesoCOOHOHHCOOHHOHCOOHOHHCOOHOHHCOOHHOHCOOHOHHCOOHHOHCOOHHOHCOOHHOHHOOCOHHHCOOHOHHOO

12、COHH232323IIIIII转180oII转60oC2 转120o23沿C2-C3C2 转120oIIIHHOOCOHCOOHHOH23COOHOHHCOOHOHH构象外消旋体）构象外消旋体）互为镜像互为镜像CH3CH3ICH3CH3II转120o1212CH3H3C12CH3CH312IIICH3CH321CH3CH321IIIH3CH3C21CH3CH312CH3CH312CH3CH312II(a,a)I(e,e)I(a,a)II(e,e)H3CH3C12H2NCOOHNH2OH2NCOOHNH2OLouis Pasteur(18221895)COONaOHHCOONH4HOHCOON

13、aHOHCOONH4OHH1848年，年，()A(+)B*(+)A(+)B*(-)A(+)B*一一对对非非对对映映体体拆拆分分(+)A(+)B*(-)A(+)B*去去除除(+)B*去去除除(+)B*(+)A(-)A接下页接下页HCH3PhNH2HCH3PhH2N+COOHOHHCOOHHOH(R,R)-(+)-酒酒石石酸酸+HCH2PhNH3COOOHHCOOHHOH+HCH3PhH3NCOOOHHCOOHHOH非非对对映映体体（盐盐）甲甲醇醇冷冷却却加加热热外外消消旋旋体体接上页接上页抽抽滤滤晶晶体体HCH3PhNH3COOOHHCOOHHOHNaOHHCH3PhNH2(S)苯苯乙乙胺胺滤滤

14、液液浓浓缩缩HCH3PhH3NCOOOHHCOOHHOH得得晶晶体体NaOH(R)苯苯乙乙胺胺HCH3PhH2N分分离离例例 1：MeMeHOHHBH2MeHHOH+(S,S)主主要要产产物物手手性性试试剂剂1.2.H2O2,NaOHe.e.=72%(R,R)%e.e.=R%-S%=R-SR+S+100%5.掌握化合物立体结构之间的相互转换。掌握化合物立体结构之间的相互转换。6.熟练掌握手性碳构型的命名，掌握手性分子的命名方式。熟练掌握手性碳构型的命名，掌握手性分子的命名方式。7.了解手性化合物的类型，熟练区分手性分子和非手性分子。了解手性化合物的类型，熟练区分手性分子和非手性分子。8.掌握旋光性、旋光异构体、旋光度、比旋光，外消旋体和内掌握旋光性、旋光异构体、旋光度、比旋光，外消旋体和内消旋体等概念，掌握其表示方式。消旋体等概念，掌握其表示方式。