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I get the whole first part of it but isn't this a base opening so shouldn't Ch3OH attack the least substituted carbon instead of the most substituted?
destroyer orgo #80
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http://forums.studentdoctor.net/showthread.php?t=553052
Ok but look at road map 6, the reaction at the very bottom. I asked this question in a previous post because the H3O+ would mean its an acidic opening but they said the H+ was used to protonate the O- to an OH. The grignard is a base and therefore its a base-catalyzed openning. If we follow this rule then #80 should also be base opening right?
Ok but look at road map 6, the reaction at the very bottom. I asked this question in a previous post because the H3O+ would mean its an acidic opening but they said the H+ was used to protonate the O- to an OH. The grignard is a base and therefore its a base-catalyzed openning. If we follow this rule then #80 should also be base opening right?
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ok, got an answer for you.
in question 80, the acid is being added at the same time and that is why there is a comma between teh two reagents.
in the road map, the gringard is added, works as a base and then the acid is used ot protonate, but only after. you can tell by the fact that in teh road map, they arent seperated by commas, rather it is a completely new number.
i hope that helps.
in question 80, the acid is being added at the same time and that is why there is a comma between teh two reagents.
in the road map, the gringard is added, works as a base and then the acid is used ot protonate, but only after. you can tell by the fact that in teh road map, they arent seperated by commas, rather it is a completely new number.
i hope that helps.
hoyas, you are misinterpreting basic organic chem semantics.
when they have a reaction and they list reagents, u assume they put all the reagents in together at once. however, this is different from when they list the reagents as: 1) xxx 2) xxxxxx 3) xxxxxxxx. This means they put xxx in, then they remove the product from the other junk, and then they put xxxxxx in, then they remove this product once again and they put xxxxxxxxx in.
By the time you get to step 4, the base is long gone.
does this help?
I read the link, and this is what he said in response to your question about road map 6
the reaction is a oxirane with a grignard. the response by albuterol is perhaps misleading because of the order in which he went about explaining it. it certainly sounds like you misunderstood him.
What Albuterol is saying is that first the grignard reacts. Since the grignard is a base, it is a base-catalyzed ring openning. This means it forms the less substituted products. However, at this point in time it is an alkoxide product because because it is in basic solution. Then the next step is to add an H+ (acidic). This happens long after the oxirane has already been cleaved. Thus the alkoxide turns into an alcohol.
does this make more sense?
when they have a reaction and they list reagents, u assume they put all the reagents in together at once. however, this is different from when they list the reagents as: 1) xxx 2) xxxxxx 3) xxxxxxxx. This means they put xxx in, then they remove the product from the other junk, and then they put xxxxxx in, then they remove this product once again and they put xxxxxxxxx in.
By the time you get to step 4, the base is long gone.
does this help?
I read the link, and this is what he said in response to your question about road map 6
the reaction is a oxirane with a grignard. the response by albuterol is perhaps misleading because of the order in which he went about explaining it. it certainly sounds like you misunderstood him.
What Albuterol is saying is that first the grignard reacts. Since the grignard is a base, it is a base-catalyzed ring openning. This means it forms the less substituted products. However, at this point in time it is an alkoxide product because because it is in basic solution. Then the next step is to add an H+ (acidic). This happens long after the oxirane has already been cleaved. Thus the alkoxide turns into an alcohol.
does this make more sense?
