Question

The major product(s) of the following reaction would be: i. AlCl3 ? lola plo cão III olą V Select one or more: Oa. Ob. 11 Oc. 111 Od. IV Oe. V

Answer 1

Answer : Major Product (V) Coption AICI: + E (v Mechanism: Friedel crafte acylation reaction: (a) Generation of electrophile (CM3os) During acylation of substituted benzene, anhydrous AlCl3 9 being Lewis acid helps in Generation of the electrophile CH3 - Ca cylium ion) by combining with the attaking reagent CH₃-Coci + Cl₂ (AlCl4] CH3- (6) Formation of carbocation Carenium ion) : Attack of electrophile results in the formation of o-complese Cors arenium ion in which one of the carbon is sp3 hybridised. signa complexe ++¢-CH3 t 7 W :-CH3 -sp2 hybridised Carbon The arenium ion gets stabilised by resonance: H H H E + 8 = _CH3

Carbonyl group (Ring I) Ring I alkyl group Ring I Attached to carbonyl group → The carbonyl group is called a deactivating group → These are groups that lower the electron density of the aromatic ring. lower the rate for an electrophilic aromatic substitutiona These groups Ring I > The Attached to alkyl group alkyl group is called an activating group Any substituent that increases the rate for an electrophilic asomatic substitution is called an activating substituent? → Thus, these alkyl group activates the ring for a faster rate. Accordingly, electrophile con acylium ion will be substituted at Ring I.

out of 1,1l, u U, TV Vi In ۱۱۱ را را a cylium ion substituted at ring I, this accordingly rejected. a cylium substituted major product Product iu (ar) product *COCH 3 R.COCH 3 Final will be either R COCH3 R COCH -H •H .H ortho R Racibo [fiering och -COCH3 + H H meka R The VI + f Kocha COCH H H H COCH₃ Para Alkyl group are election donating Therefore, It will favour electrophilic Substitution at Ortho / para positions. Conly ortho para substitution places carbocation adjacent to alkyl group on sing) often obtain more para than ortho due to steric reasons. product iv meta substituted Product v> Para substituted. Accordingly, product in Rejected

Sigma complexCareniumion) -CH3 -CH3 + The arenium ion gets stabilised by resonance: Disbios dieta 111 + (CH3 C) Removal of pooton; To restore asomatic characterao-complese releases Protoni -CH3 major product (V) Licha (v) HCl + AlCl3 (AlCl4] Answer:e. V