Microsoft PowerPoint - org6alkynes-dienes.ppt

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1 hapter 6 Alkynes and Dienes Structure Alkynes sp-hybridized 6.1 Structure, Isomerism and Nomenclature( 结构, 异构和命名 ) Electronegativity( 电负性 ):sp>sp 2 >sp The acidity of the - bonds increases. The geometry at carbon is linear. The bond becomes shorter and stronger. Nomenclature ommon names 甲基乙炔甲基乙基乙炔乙烯基乙炔 IUPA names -ane -yne 1- 戊炔 2- 戊炔 - 甲基 -1- 丁炔 Isomerism 4,4- 二甲基 -2- 戊炔 4,4-dimethyl-2-pentyne 2 l 5- 甲基 -6- 氯 -2- 庚炔 6-chloro-5-methyl-2-heptyne (E)-- 戊烯 -1- 炔 (E)--penten-1-yne (Z)-,6- 庚二烯 -1- 炔 (Z)-,6-heptadien-1-yne Alkynyl groups( 炔基 ) 2 乙炔基丙炔基炔丙基 1- 丙炔基 2- 丙炔基 4- 乙烯基 -1- 庚烯 -5- 炔 4-vinyl-1-hepten-5-yne 1- 甲基 -2- 炔丙基环己烯 1- 甲基 -2-(2- 丙炔基 ) 环己烯 1-methyl-2-(2-propynyl)cyclohexene (E)-2- 己烯 -4- 炔 (E)-2-hexen-4-yne 乙炔基 -1,,6- 庚三烯 5-ethynyl-1,,6-heptatriene l 1 4 顺 -1- 氯乙炔基 -4- 溴环己烷 cis-1-bromo-4-chloroethynylcyclohexane 1

2 6.2 Physical Properties( 物理性质 ) 6. eactions( 反应 ) 6..1 Acidity of terminal alkynes ( 末端炔烃的酸性 ) pk a = 25 pk a = 44 pk a = 50 - arbanion ( 碳负离子 ) onjugate base ( 共轭碱 ) a very weak acid( 很弱的酸 ) an exceptionally strong base( 非常强的碱 ) elative acidity( 相对酸性 ) F > S > > > > N 2 > = 2 > 2 Basicity of conjugate base ( 共轭碱的碱性 ) elative stability of anion ( 负离子的相对稳定性 ) N 2 N 4 - N Li 4 LiN S S Na Na A B - B A - (stronger acid) (stronger base) (weaker base) (weaker acid) Formation of metal alkynides ( 金属却化物的形成 ) NaN 2 liq. N : Na N LiN 2 liq. N : Li N n-buli Li n-bu Mg Mg : Na Addition to carbony compounds( 与羰基化合物的加成 ) carbony compounds( 羰基化合物 ) K 2 - press 2 2 / K press K -- Mechanism( 机理 ) B - - [Ag(N ) 2 ] Ag( 白 ) N - [u(n ) 2 ] u( 红棕 ) δ _ - - δ alogenation of terminal alkynes( 末端炔烃的卤代 ) eduction of alkynes ( 炔烃的还原 ) atalytic hydrogenation( 催化氢化 ) Lindlar s catalyst Pd-Pb/a 2 Pt Pt = syn addition Metallic palladium deposited on calcium carbonate and is poisoned with lead acetate and quinoline Lindlar's catalyst quinoline eduction with Na or Li in liquid N ( 用金属钠或金属锂在液氨中还原 ) ( 2 ) 2 Mechanism ( 2 ) 2 1)Na / N (l), -78 o 2)N 4 l ( 2 ) 2 ( 2 ) 2 anti addition N 2 Na Na - Vinylic anion - adical anion ( 自由基负离子 ) N 2 Vinylic radical ( 乙烯基自由基 ) 2

3 eduction with LiAl4( 用氢化铝锂还原 ) LiAl 4 anti addition 6.. ydroboration( 硼氢化反应 ) B / TF B syn addition Anti-Markovnikov addition Tautomerism( 互变异构 ) 2 2 / - 氧化 Enol( 烯醇式 ) Keto( 酮式 ) ' 还原 ( 2 ) 5 B / TF ( 2 ) 5 B ( 2 ) 5 ' 6..4 Electrophilic addition( 亲电加成 ) E E A / - ( 2 ) 5 E A ( 2 ) 5 2 1) 活性 : 炔烃的亲电加成比烯烃困难, 并且可以与两分子试剂加成 ( 第二步的加成更困难 ), 如控制试剂用量则可以使反应停留在一分子加成产物上 2) 区域选择性 : 加成取向遵循马氏规则 ) 立体化学 : 大多是反式加成 EA E E A A Addition with ( 与卤化氢加成 ) gem-dihalide ( 偕二卤代物 ) eactivity of alkynes( 炔的活性 ) > > eactivity of hydrogen halides ( 卤化氢的活性 ) I > > l egioselectivity( 区域选择性 ) Markovnikov s rule( 马氏规则 ) gl 2 l 2 l 150~160 Stereochemistry( 立体化学 ) anti addition ( 反式加成 ) 2 5 I 2 5 I I I 2 5 I Peroxide effect( 过氧化物效应 ) Free radical addition( 自由基加成 ) n-bu peroxide peroxide n-bu= n-bu 2 Anti-Markovnikov addition ( 反马氏加成 ) Vic-dibromide ( 邻二溴代物 ) n-bu= n-bu= n-bu n-bu 2 Addition with 2 ( 与卤素加成 ) x 2 2 l l 2 l 2 Fel l l Fel 2 l (1mol) (1mol) 2 2 Stereochemistry( 立体化学 ) anti addition ( 反式加成 ) eactivity of halogens ( 卤素的活性 ) F 2 >l 2 > 2 >I 2

4 Addition with 2 ( 与水加成 ) 2 / g 2 egioselectivity( 区域选择性 ) Markovnikov s rule( 马氏规则 ) Enol to Keto (in Acid) Enol to Keto (in Base) xidation of alkynes ( 炔烃的氧化 ) ' ' Ac 2 ' 2 1. KMn 4, ' Nuleophilic addition of alkynes ( 炔烃的亲核加成 ) N 2 =N ul base 2= 6..7 Polymerization of alkynes ( 炔烃的聚合 ) ul / N 4 l 2 2 u 2 l = 6.4 Preparation of alkynes( 炔烃的制备 ) M base, - base, - 发生两次 E2 反应, 第二次更困难 Must be 1 alkyl halide δ δ- (the alkylating agent 烷基化试剂 ) ' _ ' Bimolecular nucleophilic substitution( 双分子亲核取代 ): S N 2 v = k[ 卤代烷 ] [ 金属炔化物 ] Dehydrohalogenation of dihalides( 二卤代物脱卤化氢 ) NaN mineral oil o NaN 2 2 Na N 4l NaN 2 2 mineral oil o 2 2 K / alcohol NaN 2 / mineral oil heat 2 4

5 Migration of Triple Bond( 三键的迁移 ) Molten K or alcoholic K at 200 favors an internal alkyne. Sodium amide, NaN 2, at 150, followed by water, favors a terminal alkyne.( 熔融的氢氧化钾或者氢氧化钾醇溶液常使炔键移向链中, 而氨基钠使炔键移向链端 ) Alkylation of metal alkynide ( 金属却化物的烷基化 ) NaN 2 liq. N : Na N LiN 2 liq. N : Li N n-buli Li n-bu base base base Mg Mg δ δ- : Na M ' S N 2( 双分子亲核取代 ) Must be 1 alkyl halide (the alkylating agent 烷基化试剂 ) ' 2 - Na Na S N 2 - ' '' 2 o Alkyl halide E2 ' '' - etrosynthetic Analysis( 逆合成分析 ) anti-addition 2 - Na I - Na I 1. NaN 2/liq. N 2. I 1. NaN 2/liq. N 2. I 1. Li,EtN 2 2. N 4 l TM onjugated dienes ( 共轭二烯烃 ) 共轭二烯烃孤立二烯烃累积二烯烃 5

6 ,-yclohexadiene ,4-yclohexadiene 6.5 Structure and Physical Properties of onjugated Dienes ( 共轭二烯的结构和物理性质 ) 2 =-= 2 1,- 丁二烯 Allene not conjugated a b d e a b d e 2 2 rotate about 2 s-cis conformation s-trans conformation sp hybrid π,π-conjugation(π,π- 共轭 ) The molecular orbital theory( 分子轨道理论 ) The Ms in the 1,-butene(1,- 丁二烯的分子轨道 ) Antibonding M 反键轨道 π π 4 Antibonding M 反键轨道 π π Bonding M 成键轨道 π π 2 Bonding M 成键轨道 π π 1 6

7 The Ms in the allyl system( 烯丙基体系 ) Allyl cation ( 烯丙基正离子 ) Allyl radical ( 烯丙基自由基 ) Allyl anion ( 烯丙基负离子 ) Antibonding M 反键轨道 π Nonbonding M 非键轨道 n Bonding M 成键轨道 π 6.6 eactions of onjugated Dienes( 共轭二烯的反应 ) Aaddition with 2 or ( 与卤素或卤化氢加成 ) 2 == 2 2 == o 2 60 o 2 = 2 2 = 2 (55%) (45%) 1,2-addition direct addition 1,4-addition conjugate addition 2 = 2 2 = 2 (1%) (99%) 1,2-addition 1,4-addition 80 o o 2 (80%) (20%) 40 o 2 2 遵循马氏规则 (20%) (80%) Mechanism ,2 Product 2 1,4 Product o 40 o kinetic control or rate control ( 动力学控制或速率控制 ) o (80%) (20%) 2 2 (20%) (80%) thermodynamic or equilibrium control ( 热力学控制或平衡控制 ) 2 7

8 Thermodynamic Versus Kinetic ontrol ( 热力学控制与动力学控制比较 ) The thermodynamic product is the most stable product ( 热力学产物是最稳定的产物 ). The thermodynamic product predominates when the reaction is reversible(thermodynamic control)( 当反应可逆时, 热力学产物占主导, 即反应受热力学控制 ). The kinetic product is the product that is formed most rapidly( 动力学产物生成得最快 ) The kinetic product predominates when the reaction is irreversible (kinetic control)( 当反应不可逆时, 动力学产物占主导, 即反应受动力学控制 ). igher temperature favors the formation of the thermodynamic product( 高温有利于热力学产物的生成 ) Addition with 2 ( 与氢加成 ) 2 / Ni 1,2-addition 2 / Ni 2 =-= 2 1,4-addition 6.6. The Diels-Alder eaction 2 2 Synthetic method for preparing compounds containing a cyclohexene ring diene ( 二烯 ) Dienophile ( 亲二烯体 ) transition state cyclohexene ( 环己烯 ) tto Diels and Kurt Alder won the Nobel Prize for hemistry in 1950 for developing this reaction. N Morphine (M. Gates) holesterol (. B. Woodward) Prostaglandins F2a and E2 (E. J. orey) Vitamin B12 (A. Eschenmoser and. B. Woodward) Electrons flow from the M of the diene to the LUM of the dienophile. 2 ortisone (. B. Woodward) Me N Me 2 N Me Me Me Me eserpine (. B. Woodward) Influence of the structure of the reactants ( 反应物结构的影响 ) The diene must adopt the s-cis conformation in the transition state. Stereochemistry( 立体化学 ) syn addition( 顺式加成 ) stereospecific reaction( 立体专一反应 ) eaction is favored by electro-withdrawing groups (EWG) in the dienophile and electron-donating groups in the diene. N N N % 白 100 egioselectivity( 区域选择性 ) rtho- or Para- ( 邻 - 或对 -) 8

9 2 2 Endo product ( 内型 ) Exo product ( 外型 ) 生成内型反应速度快, 但外型更稳定 Alkynes Nomenclature Summary eactions (acidity-formation of metal acetylides, reduction-lindlar Pd ^ Na/N, hydroboration, electrophilic addition with ^ 2 ^ 2, oxidation with ^ KMn 4 )--- mechanism Preparation (dehydrohalogenation of dihalides, alkylation of metal acetylides)--- mechanism onjugated dienes 1,2- and 1,4-additions---mechanism Thermodynamic versus kinetic control Diels-Alder reaction---mechanism 9

第六章卤代烃

第六章卤代烃第八章卤代烃 Alkyl alides 1 ONTENT 1 2 3 4 5 6 卤代烃的分类结构和命名卤代烃的物理性质卤代烃的化学性质亲核取代的反应机理消除反应的反应机理卤代烃的制备 8.1 卤代烃的分类结构和命名 8.1.1 卤代烃的分类按烃基结构分类 : 饱和卤代烃不饱和卤代烃芳香卤代烃按卤原子个数分类 : 单卤代烃二卤代烃多卤代烃按卤素所连碳原子的结构分类 : 一级卤代烃