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

Step-by-step solution

The reactivity of a compound towards the S _ N 1 reaction depends on the stability of the intermediate carbocation formed after the departure of the leaving group (tosylate, - OTs ). For compound (i), the departure of - OTs yields the 1,2,3-tricyclopropylcyclopropenyl cation. This carbocation is highly stable because it is an aromatic system ( 2 electrons) and is further stabilized by the strong -conjugation (dancing resonance) from the three attached cyclopropyl groups. For compound (ii), the departure of - OTs yi