Destroyer Ochem roadmaps

[peace25]

Hi there, i think i am missing something here, can someone please expain?!
RoadMap 1:
a cyclohexane with a ketone comming off of it + Cl2 H30+ yields a cycloketone with a cl added ortho to it. i thought ketones act via addition rxns...

RoadMap 4:
ch3-c=o-c2h5 + I2, OH- yields CHI3 + c2h5coo-

RoadMap5:
ch3c=oc2H5 + Cl2 (excess), OH- yields CHCl3 + COOCH2CH3(Haloform)

RoadMap6
6member ring attached to 6member ring-CH2CN + (H30+, Heat) yields ring-ring-CH2COOH

RCONH2 + P2O5 +HEAT yields R-CN

RCONH2 + Br2, OH- (excess) yield R-NH2 (Hofmann Rearrangement)

also what is the Hoffman Elimination:
CH2(NH2, CH3) CH2 (CH3)2 + CH3I, Ag2O, H2O yields least substituated alkene

i have been dwelling over there for days and cant figure it out, so frustrating!

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[peace25]

please!? anyone understand these? any help would be muuuuuch appreciated!

 

[flybry2000]

Ahh yes the road maps...BTW, anything that I underline you should google, wiki, or refer to a text if my explanation doesn't help.

For the first reaction this is a alpha halogenation. Basically an enolate forms, and a Cl- adds to the alpha position. This is true for all dihalides (Br2, Cl2, etc.)

For the second reaction this is the Iodoform reaction. Wiki helped me to understand this one. Basically the O from OH- replaces the methyl group on the carbonyl forming a carboxylate, and iodine replaces the H's on the displaced methyl group forming CHI3.

For the third, this is generally the same as the iodoform reaction. Think of it this way, what is iodine? It's a halogen right? Yes. So, a iodoform reaction is a type of haloform reaction. Use wikipedia to look up both iodoform reaction, and haloform reaction and you will see the similarities. My way to remember these is that a Haloform reaction forms a carboxylate and an tri-substituted akly halide.

For the first of road map 6, this is the hydrolysis of a nitrile. Do you understand the carboxlic acid derivative flow chart? Basically, a ntrile is treated as a C.A. derivative, and when reacted with acid or base, and catalyzed by heat, a C.A. will form.

For the second on 6, this is the dehydration of an amide using phosphorus pentoxide. Unfortunately, this is one of those ones you need to stick in the memory bank.

For the third, Hoffman rearrangements aren't that tricky to understand. When you have a dihalide X2 (Br2, Cl2, I2...) in excess with a strong base, basically the carbonyl group (C double-bonded to O) is removed. So when you look at the road map for reference, the carbonyl group is removed from the structure of the bicycloalkane, and the amine, and the amine attatches to the bicycloalkane.

Finally, a Hoffman elimination is an Antizaitsev product. The least substituted alkene is formed. Just for fun, you should look up and realize the differences and similarities between a Hoffman elimination, and a Cope elimination.

Hope this helps.

Flybry

"Nothing comes easy, and if it did it wasn't earned."

 

[peace25]

thanks for your help,
but a few things are still kinda unclear to me,

For the first, when do you know how to do the alpha halogenation verses just a normal addition reaction?

also for the hydrolosys of a nitrile, i dont see how a nitrile is a carboxylic acid derivative

thanks for you help!