Advices For Studying Organic Chemistry

ii) lene is used as a class name for molecules with two cumulated

CH 2 =C=CH 2

The name al

double bonds.

CCC

A cumulated diene

iii) Appropriately substituted allenes g e rise to

and cumulated

vi)

2

alternate along the chain.

CH 2 =CH—CH=CH 2

Allene

iv chiral molecules.

iv) Cumulated dienes have had some commercial importance,

double bonds are occasionally found in naturally occurring molecules.

In general, cumulated dienes are less stable than isolated dienes.

) An example of a conjugated diene is 1,3-butadiene.

i) In conjugated polyenes the double and single bonds

CC

C

C

1,3-Butadiene A cconjugated diene

3) If one or more saturated carbon atoms intervene between the double bonds of an

alkadiene, the double bonds are said to be isolated.

CC

(CH 2 )n

CC

CH 2 =CH—CH 2 —CH=CH 2

An isolated diene (n ≠ 0 ) 1,4-Pentadiene

i) The double bonds of isolated double dienes undergo all of the reactions of

3.7 1,3-BUTADIENE: ELECTRON DELOCALIZATION

13.7A BOND LENGTH OF 1,3-BUTADIENE

alkenes.

1