is this a Legitimate mechanism?

[ooscubaoo]

this is what i wrote on my o chem midterm

my professor had this:

i lost 8 points because i did an "EXTRA STEP." I did a carbo cation rearrangement in it's own step instead of simultaneously when Cl was the leaving group. do you guys think this my mechanism is legitimate? if so, what is a good explanation that my mechanism works...i want a regrade but i can't because i can't back up my mechanism....thanks any info would be appreciated.

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[tanyas]

this is what i wrote on my o chem midterm
http://community.webshots.com/s/image10/3/77/74/146637774Pybryn_ph.jpg

my professor had this:

http://community.webshots.com/s/image8/3/63/11/146636311NFHKQO_ph.jpg


i lost 8 points because i did an "EXTRA STEP." I did a carbo cation rearrangement in it's own step instead of simultaneously when Cl was the leaving group. do you guys think this my mechanism is legitimate? if so, what is a good explanation that my mechanism works...i want a regrade but i can't because i can't back up my mechanism....thanks any info would be appreciated.

can't open the link

 

[ooscubaoo]

hey try to copy and paste the link in a NEW window

if i doesn't work i'll use a new server

right click my first link, go to properties, copy the ADDRESS and paste in a NEW WINDOW...it works when i do that

 

[tanyas]

still doesn't work

 

[Brill]

Angelfire doesn't allow outside links directly to images. Free servers like shutterfly or picturetrail do though.

 

[pharmaz88]

Oh geez... it's only been 2 weeks since I took my 2nd semester o-chem final, and that's already looking like Greek to me.

...better keep up some reviewing over the summer!

 

[utlonghornsandy]

I'll go check my notes

 

[utlonghornsandy]

This is what my Proffessor taught us this semester. He made it an extra step to emphasize to us that the alkylation can rearrange vs. the acylation. It might not even be wrong, maybe the grader didn't know the mechanism, so they just marked it wrong. Write that you wanted to emphasize the rearrangment to form the more stable carbocation, and that you didn't want to skip a step, in case the proff wanted to see it.

Remember in the Sn1 mechanisms, the carbocation rearrangement was an extra step also, I never learned at it as being on simultaneous movement of e-.

 

[merlin17]

I don't really want to comment on this because you already got the answer in the preallo forum but here goes...

This type of problem is meant to demonstrate knowledge of how electrons flow. You didn't demonstrate this knowledge in your mechanism when you drew the primary carbo cation. Your mechanism (for the part that the professor says is worth 8 points) is not equivalent to what the professor has written. You do not show how you are kicking that FeCl4 away...it is sort of like you are saying, the FeCl4 just leaves like a leaving group. That won't happen because a primary carbo cation is so unfavorable (thus you showed a lack of understanding of a basic principle this problem was meant to demonstrate) and you were penalized for it. That part of the problem was clearly the most difficult part, and thus it was given a high number of points by the professor. I'm sure that 90% of the people that got the mechanism wrong did the same thing. Its a good idea, but that is a pretty standard problem (probably in your orgo book as an example).

It sort of sounds like you are grade grubbing here.

 

[BenU29]

Nothing wrong with arguing about your grades. You never know how many extra points you can get