CHM136H1 Lecture Notes - Lecture 10: Cycloalkane, Ring Strain, Cyclopropane
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CHM136H1 Full Course Notes
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Examples: proteins, lipids, carbohydrates, nucleic acids, steroids. Cycloalkane structure: saturated cyclic hydrocarbons, is cnh2n, cyclohexane formula is c6h12. Cycloalkane nomenclature: lowest possible sum of numbers. Cycloalkane cis-trans isomerism: less flexible than open-chain alkanes, cannot rotate, conformational freedom . Stereoisomerism: compounds having the same atom connectivity but different 3d atomic arrangements in space, same side versus opposite sides: stereoisomers, cannot interchange by bond rotation, cis=same side, trans=opposite sides, isomerism: possible in substituted cycloalkanes, cis and trans. Oct. 4, 2016: cyclohexane is strain-free (abundant in biologically relevant compounds, but are strained due to bond bending distortions and steric interactions. Strain summary: angle: expansion or compression of bond angles away from most stable, torsional: eclipsing of bonds on neighbouring atoms (eclipsing strain, steric: repulsive interactions between non-bonded atoms in close proximity. Cycloalkane conformations: cyclopropane: must be planar, c-c-c bond angles of 60 degrees, sp3-sp3 sigma bonds are bent (and weakened, are eclipsed.
