H3C CH H2C H H H CH (4)顺-2-丁烯 5)反-2-丁烯 顺反异构 顺(cis) 反( trans) a C a+b,c丰d时存在 顺反异构体 LIYING 2021/2/10
LIYING 2021/2/10 C C H3C H CH3 H C C H3C H H CH3 (4) 顺-2-丁烯 （5）反-2-丁烯 顺反异构 顺（cis） 反（trans） C C a c b d a b, c d时存在 顺反异构体
cis-trans isomerism Different spatial arrangements Arrangements cannot be converted into one another by rotation Substituents are defined as being up or down(or left or right) with respect to a plane LIYING 2021/2/10
LIYING 2021/2/10 cis-trans Isomerism ❖Different spatial arrangements ❖ Arrangements cannot be converted into one another by rotation ❖Substituents are defined as being up or down (or left or right) with respect to a plane
cis-trans isomerism Compounds are different because it is not possible to rotate 360 degrees around any given bond Isomers cannot be interconverted by rotation Substituents can always be classified with respect to a plane in the molecule as being on one side or the other cis both substituents on same side of plane trans substituents on opposite sides of LIYING pl ane 2021/2/10
LIYING 2021/2/10 cis-trans Isomerism ❖Compounds are different because it is not possible to rotate 360 degrees around any given bond. ➢Isomers cannot be interconverted by rotation ➢Substituents can always be classified with respect to a plane in the molecule as being on one side or the other ❖cis both substituents on same side of plane ❖trans substituents on opposite sides of plane
、烯烃的命名 1.选择含双键最长的碳链作为主链(母 体),根据主链碳原子数命名为某烯 2.从靠近双键最近的一端开始编号 3.命名时双键的位次必须表明,以双键碳 原子中编号小的表示。 CH 4~2=CH2 5,5-二甲基 5.5-DimethyI-1-hexene 1-己烯 LIYING 2021/2/10
LIYING 2021/2/10 二、烯烃的命名 – 1. 选择含双键最长的碳链作为主链（母 体），根据主链碳原子数命名为某烯。 – 2. 从靠近双键最近的一端开始编号。 – 3. 命名时双键的位次必须表明，以双键碳 原子中编号小的表示。 5,5-二甲基- 1-己烯
CH2=CH2 CH3-CH=CH2 Ethene Propene Ethylene” Raylene CH3 -CH2 -CH=CH2 CH3-CH=CH--CH3 1-Butene 2-Butene LIYING 2021/2/10
LIYING 2021/2/10 CH2 CH2 CH3 CH CH2 CH3 CH2 CH CH2 CH3 CH CH CH3 Ethene Propene 1-Butene 2-Butene “Ethylene” “Propylene