[KingV15]

Explain the following reactivity order during a Lucas test:
3-methyl-1-buten-3-ol > 2-methyl-1-buten-3-ol > 3-methylbutan-2-ol > 3-methylbutan-1-ol

-I know that 3° alcohols react very fast with the Lucas reagent, secondary reacts slowly, and primary tend not to react at all at room temperature.
I am not sure how to account for the order above because I'm getting:
3-methyl-1-buten-3-ol-primary alcohol
2-methyl-1-buten-3-ol -
3-methylbutan-2-ol –Secondary alcohol
3-methylbutan-1-ol-primary alcohol
Any thoughts?

[vivekrai]

What type of mechanism does Lucas test follows : SN1 or SN2 ?? Think (check Wikipedia). And then determine what type of the reagents you have at hand.

[Arctic-Nation]

3-methyl-1-buten-3-ol-primary alcohol

Any thoughts?

Methinks you should think some more about this one. Or draw it out on a piece of paper.

[rajajidwivedi]

this is all due to stability of carbocation formed in the reaction.

[me-go]

3-methyl-1-buten-3-ol ==>  tertiary allylic alcohol ==> stable cabocation so it has fastest reaction in lucas test,

reactivity order during a Lucas test depends on carbocations:

tropylium> 3 benzylic > 3 allylic > 2 benzylic > 2 allylic > 1 benzylic > 3 > allylic > 2 > 1 > Me⁺ > vinylic > phenyl