Question

20. Explain why the diester has the highest pKa of the following 1,3-dicarbonyl derivatives. (3 points) الله الله Me Me Meo Me01 OME pka = 9 pka = 11 pka = 13 21. Explain why the desired 2º alcohol is not formed in this reaction. (3 points) 1. Meli one more OH Номме 2. H:06 not formed 22. Why does chlorobenzene react more slowly than benzene in electrophilic aromatic substitution but also direct the electrophile to the ortho para position? (3 points)

Answer 1

ketones are more Electrophilic than ester. Presence of tus & who increases the audic strength of compound by stablising the carbonion Yo Me ome ester decreases the electrophilicity of Carbonyl & hence Carbanion is less stablised & les audic me 000- Two Electron donating or two diseter decreases the Carbanion formed. Thus making it less audic. Higher the audity lower the Pka Hence this order is observed.

Me ti Hoot Que to presence of oH group. Organo metallic reagent react with Aridic proton & form me thane gas.
23.Chlorine is more electronegative than hydrogen. It draws electrons in the ring towards itself. So, it reduces the electron density of the aromatic ring of the ring.which is used for electrophillic substitution. Hence, chlorobenzene is less reactive than benzene in electrophilic substitution reaction.
Due to love pair of e available on Chlorine. They participate in the conjugation with benzene Ring. which inncreases the é density on orthon para position.