Are there a lot of mistakes on Destroyer orgo roadmaps?

[ScarletKnight24]

I believe I found one on page 111(road map #5)

from the start of secondary alcohol, it becomes 2-bromobutane and then it reacted with (CH3)3CO-K+ which is a bulky strong base so it should undergoes E2. However, why is the alkene product not showing the zaitsev's rule? Shouldn't the double bond be on the right side of the carbon with the halide?

wth???

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[DDS Perez]

Sorry but road maps are perfect.... Bulky bases give HOFFMAN product... Least stable alkene... therefore the mono-substituded alkene. If it were to be a zaitsev product it would have to be a non bulky small base. I think you got things twisted lol

Bulky Base: hoffman= least stable alkene=less substituted alkene

small un bulky base: zaitsev=more stable alkne

 

[ScarletKnight24]

Sorry but road maps are perfect.... Bulky bases give HOFFMAN product... Least stable alkene... therefore the mono-substituded alkene. If it were to be a zaitsev product it would have to be a non bulky small base. I think you got things twisted lol

Bulky Base: hoffman= least stable alkene=less substituted alkene

small un bulky base: zaitsev=more stable alkne

So it is a guarantee that you get hoffman if you have a bulky base only? even though it wasn't a tertiary halide?

 

[DDS Perez]

If its a secondary you have two possible outcomes:

1) SN2

2) E2

the strength of the base will decide which one takes place... If it is a strong negative base like Ethoxy or T-Butyl Oxide then E 2 will take place. Now depending on the bulkyness of the base is whether the product will be hoffman or zaitsev. Every time you see T-But oxide is HOFFMAN. thats the only one that they will use. There are others but they are very rare. Ethoxide is the zaitves base... and methoxide. any of those two.

P.S be careful with Hydroxide. Hydroxide is one that is very tricky. If you have hydroxide at HIGH temperatures E2 with zaitves will take place (small Base). but if you have Hydroxide with low temp SN2 will take place. thats why i said two possible outcomes.

good luck!

 

[ScarletKnight24]

If its a secondary you have two possible outcomes:

1) SN2

2) E2

the strength of the base will decide which one takes place... If it is a strong negative base like Ethoxy or T-Butyl Oxide then E 2 will take place. Now depending on the bulkyness of the base is whether the product will be hoffman or zaitsev. Every time you see T-But oxide is HOFFMAN. thats the only one that they will use. There are others but they are very rare. Ethoxide is the zaitves base... and methoxide. any of those two.

P.S be careful with Hydroxide. Hydroxide is one that is very tricky. If you have hydroxide at HIGH temperatures E2 with zaitves will take place (small Base). but if you have Hydroxide with low temp SN2 will take place. thats why i said two possible outcomes.

good luck!

Thanks.

if you have OH- (strong base & strong nucleophile) it would then depend on the electrophile right? if it is methyl or primary halide then its SN2 and secondary and tertiary would go E2.

Also ethoxide is also both a strong base and a strong nucleophile so it would be just like if it was an OH-

and according to chad if you have t-butoxy and tertiary halide then for SURE you are doing hoffman. But a t-butoxy doesn't guarantee a hoffman unless it is with a tertiary halide.

But I am just gonna do hoffman everytime I see tbutoxy