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OChem Week 3

  1. Alkynes
    Pure hydrocarbon with at least one triple bond
  2. To make Alkynes
    Take Alkenes and do it twice
  3. Double Dehydrohalogenation of Alkynes
    • Synthesis
    • Must have Vicinal Dihalide
    • Sayetzef (Poor get Poorer, Rich get Poorer)
    • alKENE to alKYNE
    • Both Halogens Leave, 2 Hydrogens Leave
    • Remember: Nitrogen likes 3 bonds (NH2)
    • Start Point: Halogens attach to carbon double bond
    • First Synthesis (Reaction in Alcohol): Alkene w/ 1 Halogen and 1 Hydrogen on double bond + H2O + K+X-
    • Second Synthesis (Reaction in NaNH2): Alkyne- No X or H on triple bond + NH3 + NA+X-
  4. Synthesis of Alkynes General Rule
    Do the synthesis and then do it again
  5. Metal Acetylides
    • Synthesis
    • Chain Lengthening
    • Will have large side group
    • Triple bond and X must be on 1o carbon
    • Remember: Nitrogen likes 3 bonds (NH2)
    • -C(triple bond)C-H (Reaction in LiNH2) -C(triple bond)C-Li + RX (Creates) -C(Triple Bond)C-R + LiX
  6. Addition of Hydrogen
    • Reaction
    • 2H2
    • Markovnikov w/ Major & Minor
    • Rich get Richer, Poor get Richer
    • Add hydrogen twice
    • Major: Na or Li (LiNH2 or Na+NH2), Creates Trans
    • Minor: H2 (Lindlar Catalyst), Creates Cis
    • alKYNE to alKENE in major/ minor
  7. Ketone
    • ---O
    • ---ll
    • R-C-R-
  8. Addition of Halogens
    • Reaction
    • 2X2 = Cl2, Br2
    • No Major/ Minor
    • Alkyne to Alkene to Haloalkane
    • Add Halogens twice
    • Alkyne (Reaction with X2) Vicinal Haloalkene (Reaction with X2) Gem-Dihalide
  9. Addition of Hydrogen Halides
    • Reaction
    • 2(HX)
    • Markovnikov w/ Major & Minor
    • Rich get Richer, Poor get Richer
    • alKYNE to alKENE to alKANE
    • ---------------------------------H X -------------------------------------------H X
    • Alkyne (Reaction w/ HX) -C=C- (Reaction w/ HX) Gem-Dihalide -C-C-
    • ----------------------------------------------------------------------------------H X
  10. Addition of water- Hydration
    • Reaction
    • Enol which is unstable
    • Markovnikov, Major/ Minor
    • Rich get Richer, Poor get poorer
    • alKYNE to alKENE to alKANE
    • Sulfuric acid provides H+, H2O provides OH-
    • H2SO4 or HgSO4
    • Major: Keto-enol
    • Minor: Ado-enol
  11. Formation of Metal Acetylides
    • Reaction
    • No Major/ Minor
    • Remains of Alkyne
    • Hydrogen on triple bond carbon leaves
    • Remember: N likes 3 bonds
  12. Tautomerism
    Repetative Part
  13. enol
    • ..H-H
    • -C=C-
  14. Ketone
    • .H..O
    • ......ll
    • -C=C-R
    • .H
  15. Aldahide
    • .H..O
    • ll
    • -C=C-H
    • .H
  16. Benzenes
    • C6H6
    • Bond length is between = and -
    • Flat ring
    • Looks like cyclohexane but isn't
  17. Kekule
    Name of Benzene ring
  18. SEA
    • Substitution
    • by an
    • Electrophile
    • on an
    • Aromatic Ring
  19. Electrophile
    • Element/ compound that is positively charged and therefore, highly drawn towards negative elements/ compounds
    • I love negative people, so I am positive
  20. Nitration
    • HONO2
  21. When you see H2SO4 and HNO3
    • Create NO2+
    • HONO2 + H+ ------> NO2 + H2O
  22. Sulfonation
    Benzene + 2H2SO in SO3 ------> H2SO4 (on ring) + H2O
  23. Halogenation of Benzene Ring
    • Benzene Ring + Cl2 in FeCl3 --------> Cl+ (on Ring) + HCl-
    • Cl- chills with the FeCl3 in the intermediate then jumps of to join H
  24. Freidal-Crafts Alklylation
    • Benzene + R-Cl in AlCl3 -------> R (on ring) + HCl-
    • Cl- chills with the AlCl3 in the intermediate then jumps of to join H
  25. Freidel- Crafts Acylation
    • .................... O......................................O
    • .....................ll........................................ll
    • Benzene + R-C-Cl in AlCl3 -----------> C-R (on ring) + HCl-
    • Cl- chills with AlCl3 before joining H
  26. If an element/ compound is on the benzene ring and has a lone pair
    It will pump electrons into the ring and therefore, the electrophile will got to Ortho/ Para Positions.
  27. If an element/ compound is on the benzene ring and is taking electrons from the ring, the carbon is partially positive
    And the electrophile will go to the Meta positions
  28. Double or Triple bonds on the benzene ring are electon withdrawals
    and are deactivating Meta Directors
  29. Ester Drinks COORRs
    • ....O
    • ....ll
    • R-C-O-R
  30. When the benzene has an Ortho/Para Director as #1...
    the Ortho/ Paras are negative
  31. When the benzene has a Meta Director as #1...
    the Ortho/ Paras are positive
  32. What position is affected on the benzene ring?
    • Ortho & Para are always affected.
    • They are either negative or positive.
  33. If you are a group on a ring withdrawing electrons...
    .... you are a deactivator meta.
  34. If you are a group on a ring giving electrons...
    ... you are an activator Ortho Para.
  35. The first group on the benzene ring goes
    ... anywhere it wants to.
  36. Creation Times of Benzene rings
    • Activator on benzene- 3minutes
    • Plain Benzene- 5minues
    • Deactivator on benzene- 8minutes
    • Halogen on Benzene- 10 minutes
  37. HOP
    • Halogens Ortho Para
    • Deactivator
  38. Lone Pairs+ Ortho Para =Activator
  39. Electron Withdrawing + Meta = Deactivator
  40. Steps to determine location of 2 groups on benzene ring
    • Isolate groups to determine location.
    • When Meta and Ortho/ Para options overlap, doesn't matter where it is located.
  41. In the event of a 'tie'/ no overlap of meta and ortho/para locations...
    ... activators defeate deactivators
  42. Aromaticity
    • 1) Cyclic, plane
    • 2) Conjugated
    • 3) Huckel's Rule
  43. Huckel's Rule
    • (4n+2) Pi electrons
    • 2pi, 6pi, 10pi, 14pi, 18pi
  44. Aromatic is ______ stable than open counter part
    MORE
  45. Anti-aromatic is ______ stable than open counterpart
    LESS
  46. Aromatic > straight Chain Equivilent > Cyclo
    comparative stability of aromatics
  47. CnH2n+2 (Alkanes)
    CnH2n (Alkenes, clycloakanes, Cis/ Trans, E-Z)
    CnH2n-2 (Alkynes, cycloalkenes)
  48. SP3
    • All alkanes (single bonds) are SP3 orbitals
    • 3 SP3 around carbon
    • 109.5o
    • Tetrahedral form around carbon
    • 1 pi bond (1.54A length)
    • 3 sigma bonds (1.10A length)
  49. Sigma Bonds
    single ponds between carbons, carbons and hydrogens
  50. Pi Bond
    The double (only 1) or triple (only 2) bond
  51. SP2
    • Alkenes
    • 1 pi bond (1.34A length)
    • planar
    • 120o
    • 3 SP2 around the carbon
    • * Aromatics are SP2
    • 2 sigma bonds(1.09A length)
  52. SP1
    • Alkyne
    • 2 pi bonds
    • Linear
    • 180o
    • 2 SP1 around carbon (1.24A length)
    • 3 sigma bonds (1.08A Length)
    • 50% spherical
  53. Bond Lengths
    • Alkane:
    • Pi: 1.54, Sigma: 1.10

    • Alkene:
    • Pi: -.2, Sigma: -.01

    • Alkyne:
    • Pi: - .1, Sigma: -.01
  54. 3o> Allyl/ Benzyl/ 2o> 1o> Ch3+
    Stability of Carbocation/ Carbon Free Radical Intermediate
  55. SNHFF
    • Sulfonation
    • Nitration
    • Halogenation
    • Freidel-Crafts Alklyation
    • Freidel-Crafts Acylation
  56. Strongly Activating Ortho Para Groups
    • H-N-H
    • H-N-R
    • R-N-R
    • O-H
  57. Moderately Activating ORtho Para Groups
    • O-R
    • H-N-O-CH3
  58. Weakly Activating Ortho Para Groups
    • R (i.e. CH2CH2CH3)
    • Benzene Ring on Benzene Ring
  59. Deactivating Meta Directors
    • NO3
    • .......CH3
    • CH3-N-CH3
    • C(triple bond) N
    • O=C-O-H
    • O=C-O-R
    • SO3H
    • O=C-H
    • O=C-R
  60. Deactivating, Ortho Para Directors
    Halogens
Author
chiroclown
ID
31997
Card Set
OChem Week 3
Description
OChem Week 3
Updated

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