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Solutions for Structure and Synthesis of Alkenes
C C
H H
PhPh
C
Ph
H
C
Ph
H
Br
Br
II
C C
Br
Br
H
Ph
H
Ph
= stretched bond being broken or formed
δ −
δ −
only geometric isomer
possible from a
concerted mechanism
both Br anti-coplanar transition state
cis
20
Ph
H Ph
Br
Br
H Ph
H Ph
Br I
Br
H
H
PhH
Ph
pi bond
cis
transition state
δ −
δ −
H
H3C H
Br
Br
H3C H
H3C H
Br I
Br
H3C
I
C C
Br
Br
H3C
H
CH3
H
C
H
CH3
C
H
H3C
Br
Br
I
H3C
C C
H3C CH3
HH
HH3C
H
= stretched bond being broken or formed
δ −
δ −
only geometric isomer
possible from a
concerted mechanism
both Br atoms anti-coplanar transition state
cis
21
(S,S)
pi bond
cis
transition state
Br atoms at 180°
δ −
δ −
157