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1、2.2 Cycloalkanes2.2.1 Classification and Nomenclature 1. Classification2024/7/30(1)saturatedunsaturatedcycloalkenecycloalkyne(2)SingleringPoly-ringspirocyclic:1carbonBridged:2andmorethan2carbon2024/7/30环数：使环状化合物变成开链化合物所需打破的碳碳键的数目。2024/7/30 2. Nomenclature of Cycloalkanes环丙烷环戊烷环丁烷环己烷2024/7/30More exa
2、mples2024/7/30 Nomenclature of the Substituted MonocycloalkanesvIfthereisonlyonesubstituent,donotusethe“1”.vIfthereismorethanonesubstituent,youmustuseallnumbers,including“1”!vNumberaroundtheringinadirectiontogetfromthefirstsubstituenttothesecondsubstituentbytheshorterpath.vForequivalentdegreesofsubs
3、titution,numberinadirectionthatfollowsthealphabeticalsequence.vAcarbonwithgreatersubstitutionhasprecedenceinnumbering.2024/7/30 1,1-Dimethylcyclohexane2024/7/30 4-Ethyl-1,1-dimethylcyclohexane2024/7/30 1-Isopropyl-2-methylcyclohexane2024/7/30 3-Cyclobutyl-3-methylpentane2024/7/30 CycloalkylGroups202
4、4/7/30Nomenclature of Monocycloalkenes1. Number from the carbon of double bond 2. Indicate substituents using the lowest possible numbers4-methylcyclohexene2024/7/302.2.2 Structure of Alicyclic Hydrocarbons1. Baeyer strain theory（1885年）年） BaeyerBaeyer张力学说建立在错误假设（认为环烷烃张力学说建立在错误假设（认为环烷烃都是平面结构）的基础上，只对小
5、环适用。都是平面结构）的基础上，只对小环适用。2024/7/30Cyclopropane环丙烷为张力环，采取重叠式构象，所以容易破环。环丙烷为张力环，采取重叠式构象，所以容易破环。此外，环丙烷此外，环丙烷CC键为弯曲键，有点类似于烯烃的键为弯曲键，有点类似于烯烃的 键，可以发生类似于烯烃的加成反应。键，可以发生类似于烯烃的加成反应。(cyclopropane has ring stain, eclipsed conformation, orbital overlap is less effective, contains more p orbital character)2024/7/30角张
6、力（角张力（Angle Strain）vExtra potential energy that a cyclic molecule may possess because bond angles are distorted in order to form a ring. 2024/7/30Cyclobutane(puckered form)蝴蝶式2024/7/30Cyclopentane信封式2024/7/30CnH2nCO2+H2O+HEATO2HeatperCH2CyclopropaneCyclobutaneCyclopentaneCyclohexaneCycloheptane166.6
7、162.7157.3156.1157.0KCal/mole2024/7/30Estimate of Angle Strain2024/7/302.2.3 Chemical properties1. Reactions similar to chain hydrocarbons (1) Halogenation (2) Addition of cycloalkenes (3) Oxidation of cycloalkenes2024/7/302. Special reactions of small cycloalkanes(1)Addition of hydrogen to open rin
8、gs 2024/7/30 (2) Addition of X2 and HX to open rings2024/7/30Cyclobutane has no such reaction at room temperature! Addition of cyclopropane deritatives with HX should obey Markovnikov Rule.区别：环丙烷对氧化剂（如高锰酸钾）稳定，而烯烃易被氧化(Difference:cyclopropaneisstabletooxidants(),whilealkeneiseasytobeoxidized)2024/7/30
9、 2.2.4 Conformation of Cyclohexane2024/7/30CyclohexaneNo angle or torsional strain2024/7/30Cyclohexanestaggered2024/7/30Cyclohexane2024/7/30Cyclohexaneno contact2024/7/30Chair Conformation2024/7/30pushuphere Boat conformationChair conformation2024/7/30BOAT CONFORMATIONFlag pole hydrogensEclipsed2024
10、/7/30Cyclohexane(topview-stericstrain)2024/7/302024/7/30Axial bondsEquatorialbonds2024/7/30Axial Equatorial2024/7/30aeeeaaaeeeaa2024/7/30axial methylequatorial methyl2024/7/30equatorial axial2024/7/30Axial MethylEquatorial Methyl2024/7/30Preferred Conformation2024/7/30Cis-Trans Isomerism of Cycloalk
11、ane2024/7/30CH3CH3HHCH3CH3HHtrans-1,2-dimethylcyclopropanecis-1,2-dimethylcyclopropane2024/7/30Stereoisomers : Such compounds, which have their atoms connected in the same way but differ in three-dimensional orientation, are called stereoisomers. 2024/7/30TransCisorTrans?2024/7/30CisCisorTrans?2024/
12、7/30CisCisorTrans?2024/7/30TransCis or Trans?2024/7/30Isomeric Dimethylcyclohexanescis-1,2trans-1,2cis-1,3trans-1,3cis-1,4trans-1,42024/7/30Isomeric Dimethylcyclohexanescis-1,2trans-1,21248.31246.8TRANSIsomerHeat Combustion More Stablecis-1,3trans-1,31245.71247.4CIScis-1,4trans-1,41247.41245.8TRANSK
13、Cal/mole2024/7/30Which has lower energy?Trans2024/7/30CisWhich has lower energy?2024/7/30axial t-butylequatorial t-butyl2024/7/30Equatorialt-butylgroup2024/7/30Axialt-butylgroup2024/7/30Large group equatorial2024/7/30Which has lower energy?Equatorial methyl2024/7/30Anti or Gauche?Anti2024/7/30TransC
14、isorTrans?2024/7/30Axial or equatorial methyl group?Axial2024/7/30Cis or trans methyl groups?Cis2024/7/30Predominant conformation of cyclohexane derivatives (环己烷衍生物优势构象的判定环己烷衍生物优势构象的判定)1.1.环己烷一取代物以取代基处于环己烷一取代物以取代基处于e-e-键上的最稳键上的最稳定定(One (One substituentsubstituent should be in the should be in the eq
15、uatorial)equatorial)2.2.含相同取代基的环己烷多元取代物最稳定的含相同取代基的环己烷多元取代物最稳定的构象是构象是e-e-取代基最多的构象取代基最多的构象(For identical (For identical substituentssubstituents, more , more substituentssubstituents in the in the equatorial are more stable)equatorial are more stable)3.3.环上有不同取代基时，大的取代基在环上有不同取代基时，大的取代基在e-e-键上键上的最稳定的最稳
16、定(different (different substituents,largesubstituents,large substituentssubstituents should in the equatorial) should in the equatorial)2024/7/30Summary Sawhorse, Newman Projection formulaStaggered, Eclipsed ConformationsAnti, GaucheAngle StrainChair, BoatAxial, Equatorial BondsPredominant conformat
17、ion2024/7/30Cyclohexane(boatform)bowsprit-flagpoleinteraction船式构象球棒模型2024/7/30Cyclohexane(topview-stericstrain)Notice!船式斯陶特模型2024/7/30Cyclohexane(axialbonds)直立键a键凡与通过分子中心的假象垂直轴平行的CH键2024/7/30Cyclohexane(equatorialbonds)凡与垂直轴成109。28的CH键2024/7/30Cyclohexane(showingbothaxialandequatorialbonds直立键平伏键2024/7/30转环作用(Ring-flip) 2024/7/30tert-Butylcyclohexane(equatorial)叔丁基环己烷2024/7/30tert-Butylcyclohexane(space-fillingmodel)叔丁基环己烷2024/7/30
