Identify the correct order of reactivity for the following compounds towards an S _ N 1 reaction: (i) (ii) (iii)

Step-by-step solution

The rate of an S_N1 reaction depends on the stability of the intermediate carbocation and the relief of steric strain upon departure of the leaving group. Isomers (i) and (iii) have their methyl groups cis to each other. After the departure of the tosylate leaving group, they form the same cis-3,5-dimethylcyclohexyl carbocation. In this carbocation, both methyl groups can adopt relatively stable pseudo-equatorial positions. Isomer (ii) has its methyl groups trans to each other and forms a trans-3,5-dimethylcyclohex