Nucleophillic attack on epoxides

[The Law]

How do you know which carbon will be the one attacked?

 

[peaceandlove]

http://www.youtube.com/watch?v=mymVqGMefdI

[The Law]

Thanks!!!

 

10charlimit

[UTPEOPLE]

Thanks!!!

 

10charlimit

 

didnt you write already? aprils almost done you know...

[supafield]

there's a lot of good orgo videos on youtube... it helped me out a bunch.

[The Law]

didnt you write already? aprils almost done you know...

 

Obviously not, otherwise why would I still be posting questions?

 

there's a lot of good orgo videos on youtube... it helped me out a bunch.

 

Ah, if only I had found this earlier!

[UTPEOPLE]

Obviously not, otherwise why would I still be posting questions?

 

Pure academic curiosity?

[The Law]

Pure academic curiosity?

 

lol, my desire for orgo knows no bounds.

[UTPEOPLE]

so when do you actually write?

[The Law]

Next week.

[UTPEOPLE]

Next week.

 

Gasp! drink lots of fluids!

[estairella]

Law with one week to go, I would ease off on trying to figure out every little concept you missed. Maybe still do one or two full lengths but spend the downtime doing quick reviews of things you do know.

 

And relax!

 

/on the morning of my MCAT, I went through my hormone flashcards... So pointless

[rmorelan]

Next week.

 

good luck!

[123coco]

I'm cheering for you law.....your determination and persistence is inspirational!

 

Cheers!

________

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[The Law]

Thanks guys!! lol, I will try not to be too crazy and realize I can't possibly learn every single fact out there! haha.

 

I just did a full length, and it went really well... so I'm hoping I can keep it up. I am still weaker in PS than the other sections, so will try to focus on that tonight and review.

[organiker]

How do you know which carbon will be the one attacked?

 

 

 

Two different sets of conditions: Under basic conditions, opening the epoxide follows the same rules as an SN2: it goes after the least sterically hindered site. So for propylene oxide, for example, the nucleophile attacks the carbon on the end preferentially.

 

Under acidic conditions, you protonate the epoxide oxygen and the situation resembles attack on a bromonium ion or mercuronium ion - it goes after the most substituted carbon, because that's the one that best stabilizes positive charge.

 

Hope this is helpful - James