Review Of Organic Chemistry Page 23
ADVERTISEMENT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34Organic Chemistry I Review: Highlights of Key Reactions, Mechanisms, and Principles
23
D. Structural Factors for Dienes
1. s-cis (cisoid) diene conformational requirement (p 682): The diene must be locked “s-cis” or be
able to single-bond rotate it’s way into the “s-cis” (cisoid) conformation in order to react
1
1
"cisoid" or "s-cis"
2
2
"transoid" or "s-trans"
-meaning that it's "cis" relative
-relative to the single bond
3
to the single bond
3
-even though the single bond
4
4
is capable of rotation
can't
can
react
react
F. Predicting Products When Both Diene and Dienophile are Asymmetric (****) (15-11B)
If either component is symmetric, you don’t have structural isomer issues.
• If both ends of diene are the same, it doesn’t matter which adds to which end of dienophile
• If both ends of dienophile are the same, it doesn’t matter which adds to which end of diene
If both components are asymmetric: two structural isomers are possible; one dominates.
****** A 1,2 or 1,4 relationship is always preferred over a 1,3 relationship, if possible *****
• Although ortho/meta/para terms don’t really correctly apply to cyclohexenes, many students
remember this is an “ortho/para preferred” rule, to avoid number confusion
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education