©gonzales2010@flickr

the last (mono)alkenes...LECTURE TEN

PREVIOUSLY...diol formation

H H

KMnO4HO OH

➒ozonolysis

i. O3(g)ii. Zn/H2O

O O

alkenescleaves

well, the steps involved...mechanism

OO

OO

OO

OO

O

Zn/H2OO O

©Renaissance Pictures

radical chemistry

to alkenesHBr

➓free radicaladdition of

HBrROOR

BrH

additionanti Markovnikov

step➊initiationmechanism

RO

OR 2x R O

R O H Br RO

H Br

radical chain reaction

electron

a radical is one

‘curly fishhook’

‘curly fishhook’

to form a bondelectrons

need two

step➋propagationmechanism

Br Br

Br H Br BrH

Br

Brchain carrier

step➌terminationmechanism

Br Br Br Br

Br Br BrBr

©Oberazzi@flickr

< <

stabilityradical

electron

missing one

➓HBr addition11to styrenes

HBr Br

H

H

Br

knownwe

but...

Ph HBr Ph

Br

H

productsingle

©Great Beyond@flickr

H Br

Br

H

H H H H

stabilisationresonance

stablecation

benzylic

H Br

H

stabilisationresonanceNO