Background

Question 1

partial bond

Answer 1

shows delocalisation of a hydrogen bond

Question 2

drawing charges on this course

Answer 2

+ or - (can circle them)

Question 3

types of σ

Answer 3

C-H & C-C v. strong, not strongly polarised, difficult to break in chemical reaction

C-X (X is heteroatom - element other than H or C but usually halogen, O or N) polarised, reactive towards nucleophilic attack

Question 4

ether

Answer 4

R1-O-R2

Question 5

amine

Answer 5

R1-NH-R2 (this is secondary, can be primary or tertiary too)

Question 6

Acid halide

Answer 6

-(C=O)-Hal

Question 7

Anhydride

Answer 7

-(C=O)-O-(C=O)-

Question 8

Amide

Answer 8

-(C=O)-N–

Question 9

nitrile

Answer 9

RCN

Question 10

disconnection arrow

Answer 10

==> (‘can be made from’)

TM = target molecule

Question 11

FMO (frontier molecular orbital approach) - what do you need for combining AOs good interaction?

Answer 11

AOs:

• close in energy
• overlap efficiently
• suitable of symmetry

Question 12

curly arrow in a mechanism represents

Answer 12

movement of electron pair from NUCELOPHILE HOMO to ELECTROPHILE HOMO
tail on filled HOMO
head on empty LUMO (electron defficient centre being attacked)

Question 13

factors to consider in what makes good MO interactions?

Answer 13

primary consdierations:

• HOMO/LUMO interactions
• electrostatic interactions

related considerations:

• hardness/softness and thus whether reaction is FMO or electrostatics driven
• orbital coefficients
• symmetry

Question 14

IA convention for what ions to not include in mechanisms

Answer 14

don’t include metal ions in mechanisms even though can technically be there