Organic Chemistry 2 Exam 1

• Alkanes are saturated hydrocarbons, while alkenes have double bonds between two carbons.
• With IR irradiation, the energy absorbed corresponds to the amount needed to increase molecular vibrations
• With UV radiation, the energy absorbed corresponds to the amount needed to promote an electron from a lower-energy orbital to a higher energy one in a conjugated molecule
• The two lower-energy, bonding MOs are occupied in the ground state, and the two higher-energy, antibonding MOs are unoccupied.
• a Diene absorbs energy and a π electron is promoted from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO). Because the electron is promoted from a bonding π molecular orbital to an antibonding π* molecular orbital, we call this a π → π* excitation (read as “pi to pi star”)
• The wavelength necessary to effect the π → π* transition in a conjugated molecule depends on the energy gap between HOMO and LUMO, which in turn depends on the nature of the conjugated system
• A conjugated diene or other compound is one that contains alternating double and single bonds. One characteristic of conjugated dienes is that they are more stable than their nonconjugated counterparts
• the two bonding orbitals are occupied; the two antibonding orbitals are unoccupied.
• The 1,2 adduct is usually formed faster and is said to be the product of kinetic control and is favored under cold conditions
• The 1,4 adduct is usually more stable and is said to be the product of thermodynamic control and is favored under hot conditions
• The greater the extent of conjugation, the less the energy needed and the longer the wavelength of radiation required.
• The IR Value of -OH is 3200-3600
• IR Value for -C=O is 1700
• IR value for Benzene Ring is 1450-1650
• IR Value for -C=O-OH is 1700, 2400-3000
• IR Value for -C=O-O-C is 1700, 1000-1300
• Odd M+ value means theres an Odd number of Nitrogens (N1, N3,N5)
• '3 O" code means:

  CH3-C=O , CH3-O, CH3-C=C-X
• Symmetry of NMR Rule:

  4H--> 2 CH2 , 6H--> 2 CH3 , 9H--> 3CH3
• '6 1' Code: Isoproyl Group

  
• '9 O' Code: Tert Butyl Group

  A) X (any compound)

  
• H-NMR of 6.5-8.0 is a Benzene ring
• H-NMR of 9-10 is -C=O-H
• H-NMR of 10-11 is -C=O-OH
• Heterotrophic has Zero Chiral Centers
• Enantiotropic has One Chiral Center
• Disaseotropic has two or more chiral
• If Hydrogen are coming off same carbon that is double bonded and One H is CIS and Other is Trans to the same reference point its Disaseotropic
• if a molecule is conjugated it will absorb UV light (200-400nm)
• longest wavelength is Red
• Shortest Wavelength is Violet
• when increase conjugation it bring HOMO and LUMO close together
• exo product is more stable than endo product
• endo product forms faster
• s- trans is more stable than s-cis because of less steric hinderance
• only s-cis can undergo Diels- Alder Rxn
• Luminescence is molecules that are colored go through emission of light when excited
• N->π* * contains lone pairs (non bonding electrons) corresponds to the excitation of an electron from one of the unshared pair to the π* orbital.
• the smaller the ΔE, the faster the reaction
• Even M+ value means theres an Even number of Nitrogens (N0,N2,N4)