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Organic chemistry B Chapter 13 Ali phatic cyclic compounds Alicyclic compounds By Prof. Dr. Adel M. Awadallah Islamic University of Gaza. Cycloalkanes: Nomenclature. Industrial source. Preparation. Reactions similar to that of alkanes (free radical substitution) , .
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Organic chemistry B Chapter 13 Aliphatic cyclic compounds Alicyclic compounds By Prof. Dr. Adel M. Awadallah Islamic University of Gaza
Reactionssimilar to that of alkanes (free radical substitution) ,
Ring Strain in Cyclopropane • Average heat of composition per CH2 = 157.4 Kcal / mol • Ring strain in cyclopropane = 27.6 Kcal/mol • Ring strain in cyclobutane = 26.3 Kcal/mol
Ring Strain in Cyclopropane • Eclipsing (torsional) strain: • Strain resulting from deviation from the staggered arrangement • Bond-Angle Strain: • Strain resulting from deviation from the normal bond angle (tetrahedral 109.5)
Addition to cyclopropaneCyclobutane undergoes hydrogenation under vigorous conditions
Relieve of torsional strain in cyclobutanePuckered structure (butterfly)
Relieve of torsional strain in cyclopentaneEnvelope (half chair) structure
1,2 + 1,4 Trans diaxial or diequatorial1,3 cis diaxial or diequatorial