CHEM 2211 1st Edition Lecture 7 Outline of Current LectureI. Ring flip with two substituents on a cyclohexaneII. Fused cyclohexane ringsIII. Functional groupsVocabularyCis isomerTrans isomerGeometric isomer1, 3-diaxial interactionsFused ringAlkaneAlkeneIsolated alkeneConjugated alkeneCycloalkaneAreneAlkyneAlcoholAlkyl halideEtherAminesCarboxyl groupAldehydeKetoneCarboxylic acidEsterAcid halideAmideCurrent LectureI. Ring Flip with two substituents on a cyclohexaneA. To predict which conformer is more stable, we must determine where the substituents areB. A cis isomer is an isomer with both groups on the same side as the ringC. A trans isomer is an isomer with one group on one side and the other group on the other side of the cyclohexaneD. These are examples of geometric isomers, molecules with the same configuration and the same bonds, but different spatial arrangementsCis-1, 4-dimethylcyclohexaneTrans-1, 4-dimethylcyclohexaneE. Remember that in order for a molecule to be a cis isomer, the substituents must be on the same side of the ring.Cis isomerTrans isomerF. Cis isomer stability vs. trans isomer stability in 1,4-dimethylcyclohexanei. Because one methyl group is in the equatorial position and the other on the axial position, each isomer is equally stable.ii. The trans isomer is a different story. The conformer with the equatorial substituents is the most stable.iii. The reason the equatorial trans isomer is more stable is because the axial trans isomer has four 1, 3-diaxial interactions.1. 1, 3-diaxial interactions- generic term for the interactions between molecules in the same planeII. Fused cyclohexane ringsA. A fused ring shares two carbons with another ring. Because of this fact, cis fused rings are less stable than trans fused rings.Trans fused ringsCis fused ringsIII. Functional GroupsA. AlkanesB. Alkenesi. Isolated alkenesSingle isolated alkeneDouble isolated alkeneii. Conjugated alkenesiii. CycloalkenesC. Arene (aka Benzene)i. An alkene with alternating double bondsD. Alkynei. Skeleton model should look like thisThe carbon to carbon triple bond must have a 180° angleE. AlcoholWhen the functional group is circled the carbon that it’s attached to must also be circledF. Alkyl Halides"X" stands for any halogenG. EtherEthers are an oxygen bonded to one or two different groupsNote that both of the carbons the oxygen is attached to are circledH. AminesPrimary, secondary, tertiary, and quaternary AminesI. Carbonyl GroupGeneric carbonyl group where Y = O, H, R, XAldehydeKetoneCarboxylic AcidEsterAcid
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