OKAY!!!! Org Chem FINAL in ONE HOUR, I HAVE ONE MORE BIG QUESTION GENIUSES, HELP!!!

[Raptor]

explain why (3S)-3-choloro-3-cyclohexylpropene has one optically active product under SN2 conditions and two optically inactive products under SN1 conditions. Provide a mechanisitic explanation that addresses the stereochemistry as well as the number of products generated. (When writing your mechanisms, you can either use a specific nucleophile or use the generic Nu-). THANKS SO MUCH YOU GUYS I HAVE A O CHEM FINAL IN ONE HOUR AND WAS PONDERING THAT QUESTION

---

Members don't see this ad.

 

[HawkeyeBFP]

Oh, fer....go get some coffee and relax. You'll be fine.

SN2 produces one optically active product because the nucleophile always attacks via a back-door mechanism, inverting the original configuration. (Whether the new stereocenter is R or S depends on what the nucleophile is.)

SN1 produces two products, because the leaving group exits before the nucleophilic attack. Therefore it can attack the carbocation from either side, which it does in equal percentages. This results in equal amounts of R and S stereoisomers and a racemic mixture, which is optically inactive.

Good luck on the final.

 

[Raptor]

dern, thanks SOOOO MUCH!!!!!!!!!!!!! THANKS THANKS THANKS....ORGANIC CHEMISTRY WILL MAKE ME CRAZY BUT THANKS AGAIN...GOOD LUCK WITH EVERYTHING

 

[HawkeyeBFP]

Yer welcome.

"This too shall pass....I've had kidney stones and I know." (Lee Hays)

 

[Raptor]

CAN you help with another problem, I will be very grateful. How many products would you expect from the reaction of 1-(2-propenyl)-3-methylcyclopentene with NBS?

THANKS THANKS THANKS

 

[Raptor]

PLEASE PLEASE PLEASE can someone help me

 

[HawkeyeBFP]

Sorry, sorry, sorry, I was away.

This is a little less clear in my memory and I don't have time to go look it up, but if I'm not mistaken NBS is the one that adds the Br to the allylic carbon (one away from the double bond). So if you have two double bonds ( and I didn't draw the molecule, but make sure both are accesible) you would have two products.

It proceeds through a single-electron intermediate, so there isn't a question of stereochemistry.

GO! Take the final!!

 

[Raptor]

thanks hawkeye, well here i go to my doom

 

[lotanna]

Hey Raptor I'm sure it went well, I'll say a prayer for you and Goodluck!!
I'm still hoping for great news this evening, u know if i call u 2night, its goin to be party time