Chapter 8, Problem 8.103CP

Interpretation Introduction

Interpretation:

Reason for benzyne to be so reactive needed to be determined.

Concept introduction:

• Carbon formed four $\sigma {\text{ bond is sp}}^3$

hybridized
Carbon formed three $\sigma {\text{ bond is sp}}^2$ hybridized
Carbon formed two $\sigma \text{ bond is sp}$ hybridized

Hybridization	Bond angle
$\begin{array}{l}{\text{sp}}^3\\ {\text{sp}}^2\\ \text{sp}\end{array}$	$\begin{array}{l}{109.5}^{°}\\ {120}^{°}\\ {180}^{°}\end{array}$

• Baeyer strain: When actual bond angle deviate from theoretical bond angle, then molecules under goes in a strain that is called Baeyer strain. Double and triple bond are more reactive than single bond single bond is formed by end to end overlapping and $\pi -\text{ bond}$in double or triple bond is formed by side to side overlapping. Side to side overlapping is less effective overlapping then end to end overlapping and double or triple bond are also electron rich, so double bond and triple bond is more reactive than single bond.

Benzyne is an unstable intermediate which has a structure similar to benzene with an additional pi bond.
According to Baeyer’s strain theory reactivity of atom is directly proportional to the Baeyer’s strain.