1 / 7

Endo-Exo Convention

Endo-Exo Convention. 1) the position of double bonds relative to rings in carbocyclic systems; 2) the relative orientation of substituents of bridged carbocycles; 3) opposing pathways for certain intramolecular cyclization and cleavage reactions;

aden
Download Presentation

Endo-Exo Convention

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Endo-Exo Convention 1) the position of double bonds relative to rings in carbocyclic systems; 2) the relative orientation of substituents of bridged carbocycles; 3) opposing pathways for certain intramolecular cyclization and cleavage reactions; 4) opposing pathways for Diels-Alder type cycloaddition reactions based on the orientation of dienes to dieneophiles.

  2. Alkene Orientations Ring Bridging 1) a bridge containing a heteroatom or atoms 2) a shorter bridge 3) a saturated bridge 4) a less substituted bridge 5) a bridge with the lowest CIP priority substituents

  3. INTRAMOLECULAR CYCLIZATIONS

  4. Example 1. Endocyclic and exocyclic double bonds: In the compound chamigrene, which was stereoselectively synthesized by transannular cyclopropanation followed by ring fragmentation, there is both an endocyclic double bond and an exocyclic double bond

  5. Example 2. 2,6-Dimethylbicyclo[3.3.1]nona-3,7- diene-endo-2,endo-6-diol. The short bridge takes precedence over the unsaturated bridges

  6. For each bridged compound below, identify the reference bridge and specify the endo/exo orientation of "W" substituent

More Related