Organic Functional Groups

Question 1

Why are alkenes reactive

Answer 1

Reactive due to being electron rich, pi electrons above and below the plane of c=c bond ate more weakly held than sigma bond

Question 2

Carbon stability (how is a carbocation stable)

Answer 2

The more C’s around cation the more stable it is.
The more H’s around cation the more reactive it is.
They are stabilised by electron density of neighbouring carbon atoms

Question 3

Properties of alkenes

Answer 3

Poor water solubility
Reactive as they are prone to oxidation=shorter shelf life
Important for medicinal chem as they form E/Z isomers which exert different biological properties

Question 4

Alkenes - alkanes

Answer 4

Hydrogen and palladium catalyst

Question 5

Alkenes- Z-1,2-diols

Answer 5

Potassium permanganate and water

The permanganate adds across double bond to form unstable intermediate, which reacts with water to generate the diol

Question 6

Alkene- E-1,2-diols

Answer 6

Peryoxyacids (RCO3H) oxidation

Peroxyacid converts alkene into an epoxide which reacts with water on the opposite side of the ring

Question 7

Alkene- carbonyl compounds

Answer 7

Ozone
Breaks the double bond, into 2, forms ketones/aldehydes
Breaks the sigma and pi bond at the same time

Question 8

Alkenes- haloalkanes

Answer 8

Halogens (cl2) or hydrohalides

Opposite sides of molecule

Question 9

Alkene synthesis

Answer 9

Alcohol dehydration ( high tems, conc H2SO4)

Wittig reaction - PH3P-R