= Solution
\b[The drawn aryl dichloride is expected to undergo no analogous substitution under ordinary ethoxide conditions.] Its chlorines are attached directly to sp2 aromatic carbons, rather than to the benzylic sp3 carbon of the previous substrate.
A normal <SN2 reaction> cannot follow the accessible backside geometry available at a primary benzylic carbon. A simple <SN1 reaction> would require a highly unfavorable aryl cation. Addition–elimination aromatic substitution would need suitable ring activation, such as a strong electron-withdrawing group in an appropriate position, which the drawing lacks. Forcing aryne chemistry cannot be inferred from ethoxide alone.
The conclusion addresses the actual E-plus-ethoxide scheme shown. The accompanying reference to replacing product B is inconsistent with the preceding substrate labels; interpreting it literally would not define the intended substitution comparison.
Back to article page
