X
R1
R2
C2-C3
O
H
H
1.55
O
Ac
H
1.538
O
Me
H
1.545
Cl,Cl
H
H
1.556
OCH
2
CH
2
O
H
Br
1.539
CHCH=C(CH
3
)
2
H
H
1.508
Table 1:
Bond length between C2 and C3 if X is changed [32].