CHM136H1 Lecture Notes - Lecture 7: Chemical Formula, Alkene, Racemic Mixture

• School: UTSG
• Department: Chemistry
• Course: CHM136H1

Document Summary

Degrees of unsaturation refer to the number of rings or multiple bonds in a molecule. Follows alkane nomenclature rules plus: name the parent hydrocarbon (longest chain must contain double bond) It"s a butene not a pentane: number c atoms to give c=c the lowest possible numbers; designated c=c location by listing number of first alkene carbon. Cannot rotate a double bond without breaking it. Cis and trans only work for dissubstituted alkenes. Assign priorities to groups on each end of double bond (use cahn-ingold prelog rule) High priority groups on the same side = z. High priority groups on opposite sides = e. Cis-2-butene is less stable than trans-2-butene due to steric strain. Cis vs trans (e)-2-butene is more stable than 1-butene. More substituted alkenes have increased stability due to hyperconjugation. Hyperconjugation: a stabilizing interaction between c-c pi bonding and c-h bonds on substituents. With ethylene there is only one possible product (bromoethane)