Question

ريل 1) 2x MgBr 2) H20 H"

Answer 1

Question A och |(1.) 2X -Mgar step 1 Step 2 B Solution Step 1 . @ ZOH (Butanoic Protonation :on Anhydride) Addition 0-4 Buton Transfer Steptotonation اين | GO H (A)

Step 2 (1-) 629.) Mg Br og mere Tetrahedral Intermediate Addition of second Mgbr 28 q.) o-Mg Br equivalent alignard reagent (care (2.) HO o-1 (B)
Initially, in step 1, we have protonated one carbonyl group of the given reactant , butanoic anhydride, using H+ to make the carbon centre more electrophillic in nature. Further the main reagent incorporated in the reaction is isopropanol. The lone pairs of oxygen atom in the OH group of isopropanol, which acts as a nucleophile, reacts with the electron deficient Carbon centre, leading to addition reaction. In the next step, proton transfer occurs followed by deprotonation gives us molecule A.

In step 2 of the reaction, one equivalent of grignard reagent, due to polarization between carbon and Magnesium, adds to the carbon atom of carbonyl group forming a tetrahedral intermediate followed by the addition of second equivalent of Grignard reagent. In the end, O-MgBr group is converted to O-H by addition of water giving us the product B.