Question

pls ans both a and b. pls remember to explain why

pls answer this one also

s Phopose s lausihic ep Write a mechanism for the reaction shown below. You must show the activated complex for both brominated positions. Based on the stability of the activated complex, propose the expected product (c-2 or C-3 bromination). Br2 Br a) FeBr3 Br Only one product is formed. Which one? Why? CH2Cl2 b) AlCl 1, NaOCH3 2. H3O NO2 NO2 OCH3 Cl

Answer 1

a) Furan bromination with Br2 to give 2-bromofuran not 3-bromofuran

Reason

Bromination second position furan to give three resonance activated complex but 3^rd position bromination give two resonance structure, product base on the stability of active complex, second position furan is more stable active complex, so 2-bromofuran only formed

B2 Febr3 Br BrHC Br CH three resonance o% Br "НС Br H Br H two resonance structure

b) 2,3-dihydro-1-benzofuran undergo friedel crafts alkylation with dichloromethane in the presence of AlCl3 to give 5-(chloromethyl)-2,3-dihydro-1-benzofuran then it will undergo friedel crafts alkylation another molecule 2,3-dihydro-1-benzofuran to give 5-(2,3-dihydro-1-benzofuran-5-ylmethyl)-2,3-dihydro-1-benzofuran

AlCh Cl CI CI AlC CI mechanism CI Cl Cl Cl CH CI CH 0

c) it is SNAr also called SN2 or ipso reaction

condition for SNAr   mechanism

The electron-withdrawing groups must be present at ortho or para to the halogen.

1-chloro-4-iodo-2-nitrobenzene undergo nucleophilic aromatic substitution reaction with NaOMe to give 4-iodo-1-methoxy-2-nitrobenzene

Reason:  The electron-withdrawing groups (NO2) present in ortho position to the chlorine substitution

0 Na+ 0 0 0- Cl CH 0 CH3