Quick Orgo (ch 3)

Question 0

Homolytic vs heterolytic cleavage

Answer 0

Homo- one electron of the bond being broken goes to each fragment of the molecule
Hetero- both electrons end up on the same atom (forms cation and anion)

Question 1

Degree of unsaturation

Answer 1

DOU = (2n+2) - x / 2
x is number of hydrogens
- include 1 for each halogen
- include 1n and 1x per N
also, for o, include 1n and 2 h's (just ignore the O!)

Question 2

Constitutional isomer

Answer 2

Aka structural isomer

Same molecular formula but connected together differently

Question 3

Conformational isomer

Answer 3

Same molecular formula, same connectivity, rotation about sigma bonds (basically same molecule)

Question 4

What are the types of conformational isomers?

Answer 4

• staggered (anti and gauche) - lowest energy/most stable

- eclipsed - highest energy/least stable

Question 5

What is envelope/chair/boat form? Most stable form?

Answer 5

Envelope: A puckered conformation for cyclopentane that allows for somewhat staggered hydrogen groups
Chair/boat: for cyclohexane
- most stable form = chair! With larger groups occupying the equatorial position

Question 6

What is deuterocyclohexane?

Answer 6

Cyclohexane with one deuterium instead of a hydrogen

Question 7

Define stereoisomerism

Answer 7

Molecules with same formula and connectivity, differing in spatial arrangement of atoms (can’t be interconnected by rotation about sigma bonds)

Question 8

Number of possible stereoisomers?

Answer 8

2^n

n is the number of choral centres

Question 9

Translate this Fischer projection: +

Answer 9

The left and right substituents point outwards and the top and bottom inwards.