Question

5. When benzamide (the reactant shown) is treated with the acylium cation electrophile shown (generated by combining concentrated acetyl chloride and aluminum trichloride), the first step of the reaction involves the benzene ring attacking the carbocation to form a sigma complex intermediate. (This curved arrows have been included in the reaction below.) Draw the sigma complex intermediate (including all resonance structures) resulting from meta attack (acyl group adds to meta carbon) and para attack (acyl group adds to para carbon) of benzamide on the electrophile shown, and place a check mark next to the major pathway in the blank space(s) provided. Use your resonance structures to justify your choice(s) in a brief explanation. Include all lone pairs and formal charges on all of your resonance structures. HaN meta attack: para attack:

Answer 1

Meta H₂ N attack! O H₂N o H₂Nyo HN H₂ N O H₂ N oo Lomplex Para attack & - H₂NYO to H₂ NO HANNO HANNO signa complex Highly Unstable H₂NO H₂N70 Ho Since these metal complexes are highly since para attack highly unstatere 6- complex. Thus, meta attack is more feasible and the major product will be meta product. Scanned with CamScanner