[orgoclear]

What is the order of migratory aptitude?

In Wiki, it is given Ph>Tert>Secondary>Primary>Methyl>Hydride

While our textbook mentions

Hydride>Ph>Tert>Secondary>Primary>Methyl

[nj_bartel]

I was under the impression hydride was at the top of the list.  Definitely isn't at the bottom.

[a student]

that's my question too, is there any logical reason for this order, I mean does anyone know that what properties are necessary for a good immigrant group?

[KritikalMass]

As with most everything in Ochem it has to do with stability and energy conservation.

What takes more energy- moving around a single puny Hydrogen atom, or moving around a whole Methyl group?

And why is it easier to move a Ph group than a tertiary carbon? Because of resonance the Ph group is stabilized. Yes it is bigger than a tertiary carbon, but since it has resonance it is lower in energy.

Why is it easier to move a tertiary carbon than secondary carbon? Because a tertiary carbon is more stable (lower in energy) than a secondary carbon.

Same reasoning applies to the rest of the question.

With Ochem always ask- What is stable? What is energy efficient?

[nj_bartel]

Tert > Sec > Methyl doesn't make sense, we're talking anions.

[exploring gul]

i have read that the group that carry more negative  charge ,will migrate because of electrostatic force of attraction energy will lower down.i agree with all this but i can t understand why the hydride has the greatest ability to migrate .in some books ph has greater migratory aptitude

[jinclean]

But in the Wolff's rearrangement the H is the top and other groups have the reverse direction