[LuckyDude35]

Ok, I have a question. I have a homework assignment that wants me to decide whether the major reaction is: proton transfer, substitution, or elimination and write them out. I need examples to tell which one to use or maybe a check list approach that I can follow to do the 10 problems. ANY help would be greatly appreciated, thank you very much!
                                        Confused in California

[Mitch]

Elimination would mean a double bond is formed. Substitution would mean an atom was replaced with an other atom. Perhaps if you posted one of the questions we can work it out with you.

[LuckyDude35]

Ok here goes:

bromomethane + hydrogen Sulfide (HS-) in DMF

Thank you very much!

[LuckyDude35]

Another one is:

1-methylcyclopentanol + HCL at 0 degrees C

I just don't know how to get started, my teacher didn't give us any examples to go off of. Thank you for your help

[Mitch]

Out of those 3 compounds are there any good leaving groups in any of them?

[LuckyDude35]

Isnt the BR a leaving group?

[Mitch]

Yes you can kinda tell the Br- is a good leaving group. Can you also tell that the HS- has a lot of electron density around it which makes is a good nuleophile?

[LuckyDude35]

I thought it was a good nucleophile but wasn't sure, so that means this is a SN1 or SN2 reaction?

[Mitch]

Which one, SN1 or SN2, likes to have the carbon be least substituted with other R-groups?

[LuckyDude35]

I know the SN2 is primary, so SN2?

[Mitch]

Yes,  I think you understand the material just sit down with it and if you still have some questions go ahead and ask them.

[LuckyDude35]

To be perfectly honest I feel like I have no idea what I am doing with some of these. I saw the DMF, and I know that is polar aprotic and i know that is supposed to be SN2, does that mean that all the one with DMF are SN2?

[LuckyDude35]

I drew out the equation and have a question, does the Br which left then attach to the H which was now alone after the S substituted for the BR?

[Mitch]

No, the S is still attached to the S. We did no Chemistry to remove it from the S.