Why Allyl Halides Are More Reactive Than Vinyl Halides

Following factors are responsible for the low reactivity of aryl halides towards nucl.

Why allyl halides are more reactive than vinyl halides.

This is because c x bond in vinyl halides have partial double bond character due to resonance. In allyl halides the double bond is in conjugation with lone pair on halides. So it is difficult to break the c x bond. The resonating structures have negative charge on terminal carbon which is very unstable and hence the allyl halides are highly reactive.

It can hold the electron pair of the bond more tightly than sp3 hybridised carbon atom in alkyl halides with less s character. As is fluoroacetate the toxic agent in the south african shrub dichapetalum cymosum known as gifblaar however the halogen rich environment of the ocean has produced many interesting natural products incorporating large. The thyroid hormones t 3 and t 4 are exceptions. Pankaj singh chemistry expert explains why aryl halides are less reactive than alkyl halides for nucleophilic substitution.

Vinyl halides are less reactive than alkyl halides. In alkyl halides carbon atom of c x bond is sp3 hybridised while in aryl halides the carbon atom attached to halogen is sp2 hybridised. Halogen containing organic compounds are relatively rare in terrestrial plants and animals. Whereas alkyl halides undergo nucleophilic substitution easily.

Aryl halides are less reactive towards nucleophilic substitution reaction due to several reasons.