H NMR Correlation

Piece of Cake right? Right?!

Molecule 21

 

Explanation

1. 7.33, 5H m. This is the only 5 H aromatic system possible
2. 6.71, 1H doublet. It is an aromatic hydrogen, and should be more upfield than Hc because it is closer to the electron donating group.
3. 6.71, 1H doublet. It is an aromatic hydrogen, and should be more downfield than Hb because it is further from the electron donating groups.
4. 5.97, 1H doublet. It is the most downfield 1H doublet because it is attached to an SP2 carbon.
5. 5.69, 1H ddd. It is the most downfield 1H ddd because it is attached to an SP2 carbon.
6. 5.05, 2H singlet. This is the only 2H singlet.
7. 4.76, 1H br. It is the only broad reading because it is the only hydrogen attached to a Nitrogen.
8. 4.56, 1H triplet. It is downfield for a SP3 carbon because it is between two oxygen groups, but it should not be a triplet.
9. 4.49, 1H d. It is the more upfield of the 1H d because it is not on an SP2 carbon.
10. 3.82, 3H singlet. It is attached to an oxygen making it more downfield, but also is more downfield than both Hl  and Hk because both of their oxygen atoms are having to compete with one another for electron density.
11. 3.36, 3H singlet. It is more downfield than Hl because it is in phase with the ring structures.
12. 3.31, 3H singlet. It is more upfield than Hk because it is out of phase with the ring structures.
13. 3.19-3.24, 1H multiplet this is the more downfield 1H multiplet because it does not have diaxial interactions with the electron donating group.
14. 2.88-2.91, 1H multiplet. This is the more upfield 1H multiplet because it has diaxial interactions witht the electron donating group.
15. 2.89, 2H singlet. It is the only 2 H singlet, but Dr. Koreeda said that these should not be categorized together because they are diastereomers.
16. 2.56, 1H ddd. This is the more upfield of the 1H ddd because it is on an SP3 carbon.
17. 0.89, 9H singlet. It is the only 9H singlet possible.
18. 0.13, 3H singlet. This is more downfield than Hs because it is in phase with the ring structure.
19. 0.02, 3H singlet. This is more upfield than Hr because it is out of phase with the ring structure.
20. These should all be 1H ddd, at least in structure 20 they kind of got by with calling it a 4H multiplet, but correct labeling would by 4 different 1H ddd.

Molecule 34

Explanation

• a: refers to the 6.42 1H d, because it is on an aromatic, and is further from the electron donating OMe group on the ring making it more de-shielded.
• b: refers to the 6.33 1H d, because it is on an aromatic, and is closer to the electron donating OMe group on the ring making it less de-shielded.
• c: refers to the 5.54 1H d, because it is the highest non aromatic 1H d due to being on a double bond, and because it is further from the electron donating OH group than d.
• d: refers to the 5.21 ddd, because it is a high value due to being on a double bond, and it has 4 bond coupling and 2 3 bond couplings.
• e: refers to the 4.69 1H d, because it is the highest valued 1 H d that isn’t on an aromatic or on a double bond.
• f: refers to the 3.84 3H singlet that is attached to the more electro negative atom Oxygen when compared to the other 3 H singlet attached to Nitrogen, making this one more de-shielded and more downfield.
• g: refers to the 3.28 1H dd, because it is more de-shielded due to the nitrogen and has 3 bond coupling
• h: refers to the 2.93 1H d, the distinguishing factor is the coupling value of 18.6 meaning a 2 bond coupling, as well as the fact that it does not couple with Hg because of its 90o orientation to it.
• i: refers to the 2.56 dd, because it has 2 ordinary 3 bond couplings.
• j: refers to the 2.51 1H dd, because it has a 4 bond coupling and a normal 3 bond coupling.
• k: refers to the 2.26 1H dd, because it has 2 bond coupling of 18.6 which we said was c, as well as coupling with e.
• l: too high, not read.
• m: refers to the 3H singlet that is attached to the nitrogen.
• ****: these four H’s on the 2 C’s should each be labeled as 1H ddd.