Organic Chemistry II - HNMR and CNMR Chemical Shift ranges

How can you tell if an atom is NMR active?

If it has an odd number of neutrons or protons, if it is inactive it will have an even amount of both.

13CNMR- peak range of 10-50ppm

-C,CH,CH2,CH3 where CH3 is closest to 0.

13CNMR- peak range of 50-25ish

Benzylic position carbon

13CNMR- peak range of 100-50

C-Y Carbons (C-N, C-O, 2 triple bonded carbons, etc.)

13CNMR- peak range of 150-100

C=C carbons and most alkenes + arenes, C triple bond N

13CNMR- peak range of 200+ -150

C=O carbons (aldehydes, ketones, carbox. acids, amides, esters)

Proton (HNMR) Chemical Shift Peak Range of 0-2

alkyl (CH, CH2, CH3) more saturated carbons ----> closer to 0

Proton (HNMR) Chemical Shift Peak Range of ~3-1.8

Allylic example: H-C-N, H-C-C=O

Proton (HNMR) Chemical Shift Peak Range of `4.8-2.5

H-C-Y protons example: H-C-X, H-C-O

Proton (HNMR) Chemical Shift Peak Range of 7-4.8

Vinyl : C=C-H

Proton (HNMR) Chemical Shift Peak Range of ~ 8.2-6.5

Aromatic

Proton (HNMR) Chemical Shift Peak Range of 12-9

Aldehydes, Ketones, Carbox. Acids (closest to 12)

What makes a good nucleophile? 6 things

1. charge: negative charge better

2. EN: less EN better Nu

3. Size: if in same group bigger is better

4. Steric Hinderance: bulky BAD!

5. Resonance: more resonance BAD!

6. Solvent: polar protic BIG!/ aprotic SMALL!

What solvent does Sn2 and E2 want?

Polar protic

What solvent does Sn1 and E1 want?

Polar aprotic

Saturation and solevent preference for Sn1, Sn2, E1, E2

Sn1: 3 sometimes 2. wn/wb

Sn2: 1 sometimes 2, sn/wb

E1: 3 and 2, with heat wnwb

E2: any, wn/sb

E2 antiperiplanar

removal of the most substituted ß-H

EXCEPTIONS: F is LG, base is too substituted, if it is in a cyclic ring

Hydrohalogenation

• Carbocation forming

• markovnikov

• no stereo preference

Hydrobromination

• no carbocation

• reacts with peroxides

• antimark

• no stereopreference

• ONLY Br

Acid-catalyzed and modified

• carbocation

• mark

• no stereo pref

• modified is with using OH instead of water

• if water used it turns into OH

• if OH used turns into ether

Halogenation and modified

• mark

• anti addition

• if using NPS X added to both sides anti

• if using PS add X to one and OH to other side anti with OH being on most sub

• modified: is just using a haloether same rules as before

Oxymercuration demercuration

• Anti?

• mark

• creates cyclic intermediate with Hg with H2O opening ring and NaBH4 removing Hg leaving an OH on the mark side

• modified with OEt

Hydroboration

• syn

• anti-mark

• B attacks back but no cyclic intermediate and one of the H from B will attack back and add a H to most sub side

• ends with H and OH added syn

Catalytic Hydrogenation

• H2 and some catalyst

• removes all double bonds except for arene

epoxidation

• 3 member ring with O using a peroxide mCPBA, RCO3H

• mark

• syn

anti dihydroxylation

• epoxide opening up anti

• anti mark

• using SN2 and water to attack

Syn dihydroxylation

• same concept as anti except with OSO4 bonding and leaving syn OH