Sn1 products 50:50?

[gangazi]

For the DAT test purpose, do we say Sn1 yields 50:50?

---

Members don't see this ad.

 

[Likkriue]

You say it yields a racemic mixture which is essentially 50:50 r+ s.

 

[juandhy]

If you wanted to be nitpicky you could say that you'll yield slightly more than 50% of the inversion product due to sterics.
It's not a "true" racemization, but they still use that term.

 

[DAT Destroyer]

For the DAT test purpose, do we say Sn1 yields 50:50?

Let's review some basic facts. The Sn2 reaction always gives 100 percent inversion, that is easy enough. For the DAT exam you will assume that an Sn1 gives a 50/50 mixture of enantiomers, we call this a racemic mixture. However, in real life we rarely get a 50/50 mixture because the solvent has not completely aided in the separation of the leaving group and a backside attack occurs. This means we get a slightly more of the inversion product and not 50/50. We call this a scalemic mixture. This is not necessary for the DAT but for your own curiosity. If conditions are very polar such as an aqueous environment we get good separation of the leaving group and form a carbocation which can be attacked from top and bottom face to give a racemic mixture. Bottom line: assume a 50/50 mix for an Sn1.

Hope this helps

Dr. Romano

 

[gangazi]

Let's review some basic facts. The Sn2 reaction always gives 100 percent inversion, that is easy enough. For the DAT exam you will assume that an Sn1 gives a 50/50 mixture of enantiomers, we call this a racemic mixture. However, in real life we rarely get a 50/50 mixture because the solvent has not completely aided in the separation of the leaving group and a backside attack occurs. This means we get a slightly more of the inversion product and not 50/50. We call this a scalemic mixture. This is not necessary for the DAT but for your own curiosity. If conditions are very polar such as an aqueous environment we get good separation of the leaving group and form a carbocation which can be attacked from top and bottom face to give a racemic mixture. Bottom line: assume a 50/50 mix for an Sn1.

Hope this helps

Dr. Romano

Thank you Dr. Romano! That helps A LOT!

 

[gangazi]

In this problem, I was expecting the answer to be "product will be mixture because Sn2 and E2 occurs at the same time" because NaOH is a strong Nu/Base and used secondary halide.
However, none of the answer choices are like that. AM I missing something? Thank you SDNers and DR. Romano