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Chapter 11 407
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48.
a.
b.
c.
CH
3
O
O
49.
Some alkenes can undergo ring-opening metathesis to form high-molecular-weight polymers. Relieving
the strain of a ring that contains a double bond (recall that
sp
2
carbons have 120
°
bond angles) causes the
reaction to go to completion.
a.
First draw the product obtained by breaking the double bond and forming new double bonds. Seeing
that six-membered rings are formed allows you to draw a reasonable structure for the polymer.
CH CHCHCH
2
CH
2
CHCH CHCHCH
2
CH
2
CHCH CH
CH CH
CH CH
CH CH
b.
CH CHCHCH
2
CH
2
CHCH CHCHCH
2
CH
2
CHCH CH
CH CH
CH CH
CH CH