Question

Circle the reaction that is faster for each given pair of reactions and concisely explain your reasoning, being certain to clearly indicate the type of mechanism operating in each case. 1-Buok BA t-BuOH -Buok -BuOH isopropanol heat isopropanol heat

Answer 1

e) In the case of the 1-bromo-4-iso propyl cyclohexane isomers, the iso propyl group is so large that it will always assume an equatorial orientation, leaving the bromine to be axial in the cis-isomer and equatorial in the trans. Because of symmetry, the two axial beta-hydrogens in the cis-isomer react equally with base, resulting in rapid elimination to the same alkene. so the first one will react fast.

f) Reaction follow E¹CB mechanism as 2^o Carbanion is more stable than 3^o So the Second reactant will give faster and Stable product.

In the last case also the first reactant will give faster as well as stable product.  

KOH alcohol Cilisomer " wauti) fost r eaction DATORI KOH 1 alesher of very slow Ci will give faster EQ - Product H Isopropanol Heat feb To 3 Carbocation les stable my low yield High yeild 2 Roactant -Panol Fast Carbocation more stable give faster Product and H SNS allylie Carbocation more stable Fost one rotest Product - Plast one give fastest Product SNI Not possible SN -0 Slow i net formed