Cycloalkanes Flashcards
Why do cycloalkane undergo conformational change?
Cycloalkane will want to change its conformation to become more stable so it can avoid strains (angle, torsional and steric)
Which cycloalkane is the most strained?
Cyclopropane is the most strained of all rings due to angle strain and torsional strain
What is angle strain?
When bond angles are forced to deviate from the ideal 109 tetrahedral value
What is torsional strain
Strains due to eclipsing of bonds between neighboring atoms
What is the result of cyclopropane being stuck in its planar and strained conformation?
It cannot do anything to relieve the angle and torsional strain it is experiencing
Why does cyclobutane has torsional strain
There are 8 eclipsing C-H bond
How does cyclobutane and cyclopentane relieve its strain?
Through ring puckering
What is ring puckering?
When hydrogens are twisted away from each other to reduce eclipsing
Why does cyclopentane have almost no angle strain?
It has a 108 degree bond angle
Why does cyclopentane have a lot of torsional strain?
There are 10 eclipsing C-H bond
Why does cyclohexane have angle strain and torsional strain?
Cyclohexane has a bond angle of 120 which deviates from the ideal 109. It has a lot of torsional strain because it has 12 eclipsing C-H bonds
What are the conformation cyclohxane can take from ring puckering?
Chair, Boat, Twist Boat, Half Chair
Rank cyclohexane’s conformation from increasing energy
Chair, twist boat, boat, half chair
Chair is the most stable and half chair is the least stable
What is the most stable cyclohexane conformation?
Chair conformation of cyclohexane
What is a ring flip?
When the Carbons in a cycloalkane shifted one position from its original position in a clockwise manner
