Destroyer Orgo #100

[kaDa]

In #100, why does the second reaction result in the monosubstituted alkene instead of the disubstituted? Is it b/c of the bulky base? If so, does #83 go through because that is only one hydrogen available for E2? (This is in the 2009 version)

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[joonkimdds]

Ok first of all, OH is replaced by Cl~

and then we have 2 chloro butane.

The second reaction is bulky strong base with alcohol. This means there will be E2 reaction and it will form C=C with less stable one.

I don't understand what mono-,di substituted refers to.


and for #83, I believe u r correct. U got no choice but to form C=C with that.

 

[kaDa]

Sorry, mono substituted means the alkene forms on the end of the molecule. Di substituted means alkene formation in the middle. I believe the terminology refers to the R groups on either side (so mono has one R group and Di has two). I always though E2 formed the most stable alkene, so I would think this would mean it would want the double bond in the middle. (I guess this refers to Zaitsev's rule)

I was trying to cite #83 as an example of this not happening, but only because it was not possible for any other alkene to form. I think it is getting away from the focus of my question tho, so I apologize .

 

[Extirpator]

In #100, why does the second reaction result in the monosubstituted alkene instead of the disubstituted? Is it b/c of the bulky base? If so, does #83 go through because that is only one hydrogen available for E2? (This is in the 2009 version)

Both of your explanations are correct

 

[kaDa]

OK, so an unhindered base (like OH) will probably end up with an internal alkene...thanks!