The carbocation electrophile in a Friedel-Crafts reaction can be gener- ated by an alternate means than reaction of an alkyl chloride with AlCl3. For example, reaction of benzene with 2-methylpropene in the presence of H3PO4 yields tert-butylbenzene. Propose a mechanism for this reaction. +

Ph- OC XT :OH₂ Primary amines add to aldehydes and ketones to give imines. Imines are formed in a reversible, acid-catalyzed process that begins with nucleophilic addition of the primary amine to the carbonyl group, followed by transfer of the proton to yield a neutral carbinolamine. Protonation of the hydroxyl group converts it into a good leaving group and an E1-like loss of water yields an iminium ion. Deprotonation yields the product imine and regenerates the acid catalyst. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions NHOH CH3 CH3 NH₂OH OH HN I Ph CH3 OH H₂O CH3 за

Decide which compounds from the list below are best suited for nucleophilic addition reactions and which ones are more appropriate for nucleophilic substitution reactions.

Propose a mechanism for the conversion of E to F. The reagent used in this synthesis is ethyl chloroformate. The other product of this conversion is chloromethane, CH3Cl. Your mechanism should show how the CH3Cl is formed.

1. Propose reasonable mechanisms for the following transformations: OH H+ 女 Η

Propose a mechanism for the following reactions.

4. Using resonance structures, show how the intermediate is stabilized in the reaction of p-chloronitrobenzene with pyrrolidine in the substitution reaction shown: NO 2 NO2 H N. N CI +