A few quick OChem Rxn Questions

[BiomajorPreDent]

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1. In destroyer road map 6 at the bottom it has a grignard CH3MgCl attacking an epoxide and it says it attacks the less substituted C since its a base. I know how epoxides react, but is destroyer saying the grignard itself is a base? As I am writing this I remember reading about grignards being strong bases, I just wanna make sure I have it right.

2. Hoffman Rearrangement? I cant find it in my textbook, basically from destroyer road map number 6, its a amide reacting with excess Br2,OH- to form a primary amine. Can someone explain this to me?

3. There are two other reactions one involving an alkyl halide and the other an acyl chloride. In each one its reacting with (CH3)2CuLi in ether. From the looks of it, it just replacing the halogen with a CH3 group. Am I missing anything here, I havent seen this reaction before. Are there any other reagents or conditions this could be carried out in that I should know about?

4. Finally, on roadmap 5, there is a reaction called Simmons Smith which I could not find in my book. Its reacting a trans alkene with CH2Cl2,Zn(or Cu) in ether and giving some kind of small ring I dont even know how to describe it lol. Could anyone shed light on this reaction?

Thanks alot!

 

[BiomajorPreDent]

bump

anyone?

 

[alanan84]

1. In destroyer road map 6 at the bottom it has a grignard CH3MgCl attacking an epoxide and it says it attacks the less substituted C since its a base. I know how epoxides react, but is destroyer saying the grignard itself is a base? As I am writing this I remember reading about grignards being strong bases, I just wanna make sure I have it right.

Yes grignards are strong bases because they resemble carbanions.
R-Mg-X reacts like R:- Mg+X

2. Hoffman Rearrangement? I cant find it in my textbook, basically from destroyer road map number 6, its a amide reacting with excess Br2,OH- to form a primary amine. Can someone explain this to me?

The rxn uses a base and either Cl2 or Br2 and just takes the whole carbonyl group away forming the primary amine from the amide. The mechanism is complicated so I don't think we need to worry about that.

3. There are two other reactions one involving an alkyl halide and the other an acyl chloride. In each one its reacting with (CH3)2CuLi in ether. From the looks of it, it just replacing the halogen with a CH3 group. Am I missing anything here, I havent seen this reaction before. Are there any other reagents or conditions this could be carried out in that I should know about?

Sounds like a regular organolithium rxn to me.

4. Finally, on roadmap 5, there is a reaction called Simmons Smith which I could not find in my book. Its reacting a trans alkene with CH2Cl2,Zn(or Cu) in ether and giving some kind of small ring I dont even know how to describe it lol. Could anyone shed light on this reaction?

I don't remember learning this in my ochem class but it's in my book. It's just exactly as you described it. It looks like you have to use that exact reagent every time. Doubt it'll be on the DAT.

Thanks alot!

There's my input

 

[BiomajorPreDent]

thanks 🙂

 

[navneetdh]

http://alpha.chem.umb.edu/chemistry/orgchem/CH20Handout.pdf


i had the same question about hoffman. this link is very helpful 🙂

 

[BiomajorPreDent]

I ressurected this thread because I finally figured out what the reaction was with the reagent: (CH3)2CuLi in Hexane or Ether

(note that it doesnt have to be CH3 in the parenthesis it could be another R group)

Yes it is an organolithium compound like alanan84 stated, but it is known as a Gilman reagent

Just incase anyone else saw this in destroyer and was confused.

It basically reacts with an alkyl halide (except flourides) and one of the alkyl groups of the Gilman reagent replaces the halogen

It can be useful to react with compounds that do not undergo Sn2 reactions like vinylic and aryl halides and can also attack other functional groups such as ketones and acyl halides

I dont know the odds of this showing up, but I am happy I know it now 🙂