Organic Chemistry / Leaving Group Conversions - Using HX
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Solution: Assuming that the rate-determining step in the reaction of 1...

Question

Assuming that the rate-determining step in the reaction of 1-hexanol with hydrogen bromide to give 1-bromohexane is an attack by a nucleophile on an alkyloxonium ion, write an equation for this step. Use curved arrows to show the flow of electrons. 

Video Transcript

Hey everyone. In this question we have our 1-hexanol reacting with hydrogen bromide to give us our 1-bromohexane and what we're going to show is the nucleophilic attack on our water molecule, that's going to be the rate determining step. So, note that what we need to show is we're going to take the six carbon chain here, with an alcohol and we're going to show that it's going to turn into a water, okay? So the attack of the nucleophile is going to be after our oxygen comes in and grabs a hydrogen, it's going to break this bond, since we have a primary alcohol reactant here we're going to be doing an SN2 type reaction. So, after we form this water it's simply not going to leave on its own it's going to be attacked by a nucleophile, in that nucleophile is going to be this bromine that has a negative charge, what's going to happen is this is going to come in and do a backside attack and kick off our water, alright? So, once this happens we would expect to get a product that looks something like this, and it's already drawn in, so let's just show our arrow right here, this is going to be our expected product right here in the box, okay? So the rate determine step that I was talking about will be a slow step occurring right here, that is the attack of our nucleophile being this bromine ion on our water, okay? So, just remember that this is going to proceed during SN2 mechanism, first we're are going to take our alcohol and protonated with our acid and then our bromide ion will do that nucleophilic attack, okay? So I hope this made sense and let me know if you guys have any questions.