Question

if full explanations can be provided it would be appreciated

Propose a mechanism that explains formation of the products from the following reaction, including the distribution of the products as major and minor. [6] H.SO. (cat.) Major Minor 11 11 111mm in tuanted with

Answer 1

Answer:

In presence of strong acid like H2SO4, Rgioselective electrophilic addition of proton to alkene takes place. Regios electivity is govemed by the stability of Carbocation would be forming. As 3º Carbocation is far more stable than 1° carbocation the result of protonation is the formation of 3° carbocation. HOS H2SO4 HOS Regioselective addition of proton 3º Carboc ation Bisulphate ion Resonance Stabilized Then as bisulphate ion is weak base and even non-nucleophilic hence an another molecule of isobutene with pi cloud attack self carbocation. This step is also a regioselectively driven as first step. Hence the follwing carbocation results, HOZ Non-hindered 00 Sterically hindered proton due to bulky quatemary carbon. 1 H₂C H CH₃ H3C FCH2 H₃C CH-CH3 H₃C C-ch 1 H₃C H₃ C (a) CH₃ H CH In absence of further isobutene molecule, only bisulphate ion is possibly a base which H3CH3C Major CH3 abstract proton from beta position to ketone and H2C gives alkene compound. Buisulphate being bulky molecule prefer least hindered proton and gives corresponding H3C Hссна Minor alkene as major.

================XXXXXXXXX===========