1.12 CYCLIC ALKANES cyclopropane cyclopentane cyclobutane Chp 1.12 cyclic alkanes 1.12 CYCLIC ALKANES cyclopropane cyclopentane cyclobutane

MORE CYCLOALKANES ( cyclo = ring ) cyclopentane cyclohexane Chp 1.12 cyclic alkanes MORE CYCLOALKANES ( cyclo = ring ) cyclopentane MOST STABLE cyclohexane

COMMON ORGANICS THAT CONTAIN RINGS nicotine cholesterol mescaline caffeine

1.13 Naming cyclic alkanes

RINGS WITH ONE SUBSTITUENT Chp 1.12 cyclic alkanes RINGS WITH ONE SUBSTITUENT sec-butylcyclohexane No locant is needed. With one substituent on a ring , it is automatically on carbon 1.

= SOME CYCLOALKANES C H C H C H C H 1,3-dimethylcyclopentane Chp 1.12 cyclic alkanes SOME CYCLOALKANES C H 3 1,3-dimethylcyclopentane Drawn differently but same name. C H 3 2 1 = 3 C H 3 2 Begin numbering the ring at one of the attached groups, so that the attached groups have the lowest numbers. C H 3 2 4 3 1 2 2 1 3 3-ethyl-1,1-dimethylcyclobutane 1-ethyl-4-methylcyclohexane The more substituted carbon takes precedence even though E comes before M. E before M

C H C H C H C H C C H C H NAMES OF THE COMMON ALKYL GROUPS ARE Chp 1.12 cyclic alkanes NAMES OF THE COMMON ALKYL GROUPS ARE ALSO USEFUL WITH CYCLIC COMPOUNDS isopropylcyclohexane C H C H 3 C H 3 2-cyclohexylpropane C H 3 C C H 3 C H 3 tert-butylcyclopentane You can base the name on either the RING or the LONGEST CHAIN 2-cyclopentyl-2-methylpropane

Chp 1.12 cyclic alkanes Name This 1-isopropyl-2-methylcyclohexane

1.14 Isomerism in cyclic alkanes Constitutional isomerism Stereoisomerism

Constitutional Isomers of Chp 1.12 cyclic alkanes Constitutional Isomers of C7H14 C H 3 C H 3 C H 3 C H 3 1,3-dimethylcyclopentane 1,1-dimethylcyclopentane C H 3 C H 3 1,2-dimethylcyclopentane

More constitutional isomers of Chp 1.12 cyclic alkanes More constitutional isomers of C7H14 CAN YOU THINK OF ANY MORE?

Stereoismerism in cyclic alkanes 1. Occurs in cyclic alkanes with two or more groups attached to the ring. 2. Attached groups do not have to be the same. 3. Attached groups must be on different carbon atoms. 4. The stereoisomers are named “cis” and “trans”

Stereoismerism in cyclic alkanes (cont) We will only consider the stereoisomerism in rings with two attached groups. 1. cis : the groups are on the same side of the ring (above or below)

Stereoismerism in cyclic alkanes (cont) 2. trans : the groups are on opposite sides of the ring (one group above and one group below)

Stereoisomers of 1,3–dimethylcyclopetane Chp 1.12 cyclic alkanes Stereoisomers of 1,3–dimethylcyclopetane C H 3 cis-1,3-dimethylcyclopentane C H 3 trans-1,3-dimethylcyclopentane C H 3 cis-1,3-dimethylcyclopentane C H 3 trans-1,3-dimethylcyclopentane

Stereoisomers of 1,2–dimethylcyclopentane Chp 1.12 cyclic alkanes Stereoisomers of 1,2–dimethylcyclopentane C H 3 cis-1,2-dimethylcyclopentane C H 3 trans-1,2-dimethylcyclopentane C H 3 cis-1,2-dimethylcyclopentane C H 3 trans-1,2-dimethylcyclopentane

1,1-dimethylcyclopentane Chp 1.12 cyclic alkanes 1,1-dimethylcyclopentane C H 3 Neither cis nor trans Attached groups must be on different carbon atoms

1.15 Sources of alkanes

1.16 Physical properties of alkanes Water solubility B.P. and M.P Branched Linear Cyclo Increasing M.W.

1.17 Chemical Properties Combustion…… Write balanced equations Energy source CO2 and H2O are products Write balanced equations

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