CHEM 2443 Chapter Notes - Chapter 8: Joule, Cycloheptane, Furan
Document Summary
This flattening is due to the presence of an odd number of carbons in the ring and it means that there will be some torsion strain due to eclipsing bonds and atoms in this form of cycloheptane. Some twisting of the ring can occur to relieve this strain, but such pseudorotation may increase strain elsewhere in the molecule. There are several other conformations for cycloheptane, as there are for cyclohexane because the size and flexibility of the ring has increased but, at this point, no other conformations for cycloheptane will be discussed. Medium rings & transannular strain: 2 medium-sized cyclic alkanes, cyclooctane 62a and cycloundecane 63 are shown as 2d (planar) conformations that do not represent their 3d structure, with larger rings there are several relatively low energy conformations. Sight down the cavity for a different perspective: 62d. Space-filling model 62e shows that these h atoms are relatively close together.
