有机化学第三章立体化学

1、同分异构构造异构立体异构碳链（碳架）异构官能团位置异构官能团异构互变异构构型异构构象异构顺反异构光学异构例：庚烷碳链异构体数目最长直链：C C C C C C C缩短一个C接到相应缩短后的碳链上：C C C C C CCC C C C C CC缩短二个C接到相应缩短后的碳链上：C C C C CC CC C C C CCCC C C C CCCC C C C CCCC C C C CCC12345678缩短三个C接到相应缩短后的碳链上：C C C CCC CC C C CC C CC C C CC C CC C C CCCC9同4同3同4CH3CH2CH2CH2Br1-溴丁烷CH3CH2CHC

2、H3Br2-溴丁烷CH3CHCH2BrCH32-甲基-1-溴丙烷CBrCH3CH3CH32-甲基-2-溴丙烷CH3CCH2CCH3OOCH3CCH CCH3OOHHH3CHCH3HH3CHCH3H3CCH3H3CCH3cistransHHHHHHHHHHHHCCCH3HCH3HCCHCH3CH3H顺-2-丁烯反-2-丁烯CCHCH3ClC2H5CCHClCH3C2H5(Z)-2-氯-2-戊烯(E)-2-氯-2-戊烯CCHHCH3CCHCH3COOH(2E, 4Z)-3-甲基-2, 4-己二烯酸CCCH3C2H5CH3H反-3-甲基-2-戊烯(Z)-3-甲基-2-戊烯CCHOOCHCH2HCCC

3、OOHHH(2Z, 5E)-2, 5-庚二烯-1, 7-二酸chiral 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CH3HOHHOHCH3CH3HOHOHHCH3CH3OHHHOHCH3IIIIIICH3HOHHHOCH3I对映关系对映关系CH3HOHHOHCH3IIICH3

4、OHHHHOCH3IIICH3HOHHOHCH3IIICH3C2H5HOHCH3CC2H5OHHCH3C2H5OHH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2CH3HOHHOHCH3III3CH3OHHCH3OHH23CH3HOHCH3OHH23IICH3OHHCH3HOH23IIIICH3O

5、HHCH3OHH23u手性化合物的特性手性化合物的特性旋光性（旋光度旋光性（旋光度a a、比旋光，外消旋体和内消旋体）比旋光，外消旋体和内消旋体）CH3C2H5HOHH3CC2H5OHHCH3C2H5HOHCH3C2H5HOH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IIICHO

6、CH2OHHOH交交换换 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

7、非对对映映异异构构体体交交换换 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 -CH2O

8、H -CH(CH3)2 -CH2CH(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CCH3CH3CH3CCCCH3CH3CH3CH3HOHCH3OHH23IICH3OHHCH3HOH23IIIICH3OHHCH3OHH23CH3OHHCH3HOH23ICH3HOHH3COHH23CH3HOHH3COHH23CH3HOHCH3OHH23IICH3OHHCH3HOH23III

9、ICH3OHHCH3OHH23手性碳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C

10、H3OHHCH3OHHCH3OHHCH3ClHHFHClFHClHHFHClFHClHHFHClFH180oCOOHHHOHHO23HOHCOOH4COOHHHOHOH23HOHCOOH4COOHHHOHHO23OHHCOOH4COOHHOHHOH23HOHCOOH4SRrSRsSSRRl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*COOHHOHCOOHOHHCO

11、OHOHHCOOHHOHCOOHOHHCOOHOHH(R,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

12、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向偏转，两者偏转两者偏转数值相同数值相同。COOHHOHCOOHOHHCOOHOHHCOOHHOH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

13、中溶解度pK1pK2COOHHOHCOOHOHH171-174oC210-212oC146-148oC1.76g / cm31.70g / cm31.66g / cm3139g / 100ml21g / 100ml125g / 100ml2.984.344.244.822.963.23COOHOHHCOOHHOH mesoCOOHOHHCOOHHOHCOOHOHHCOOHOHHCH3HOHCH3OHH23CH3OHHCH3HOH23CH3OHHCH3OHH23OHHCH2OHCHOHOHCH2OHCHOCHOHHOOHHOHHCH2OHOHHHCOOHCH3OHHCOOHCH3HOOHHCH2

14、OHCHOHOHCH2OHCHOCOOHHOHCOOHOHHCOOHOHHCOOHHOHCOOHOHHCOOHOHH5050H2NCOOHNH2OH2NCOOHNH2ONNOOOPhn-BuH3CHNNOOOPhn-BuCH3HHOHOCOOHNH2HOHOCOOHNH2NOONHOONOOHNOOLouis Pasteur (18221895)COONaOHHCOONH4HOHCOONaHOHCOONH4OHH1848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(-) AH2NCOOHCH3HNH2COOHCH3HL 丙丙氨氨酸酸D 丙丙氨氨酸酸()-丙丙氨氨酸酸Ac2OAcHNCOOHCH3HNHAcCOOHCH3H+外外消消旋旋体体酰基转移酶（取自猪肾）H2NCOOHCH3H+L 丙丙氨氨酸酸D 乙乙酰酰丙丙氨氨酸酸溶溶于于乙乙醇醇不不溶溶于于乙乙醇醇NHAcCOOHCH3H选择性去乙酰基选择性去乙酰基William S. Knowles The Nobel Prize in Chemistry 2001 for their work on chirally catalysed hydrogen