[treadlightly]

I have phenyl acetate undergoing nitration. It is supposedly going to add NO2 at the ortho and para position, but should I expect any ortho products? Is the acetyl group in phenyl acetate big enough to prevent any ortho products from forming?
A little insight as to why would definitely be helpful =]
Thanks!

EDIT: Phenyl acetate: http://upload.wikimedia.org/wikipedia/commons/thumb/e/ec/Phenyl_acetate.svg/512px-Phenyl_acetate.svg.png

[magician4]

usually, ortho/para regioselectivity is something most difficult to predict: steric factors are not the only game in town
additionally, we at times observe a high dependency of the very fines of reaction conditions. For example, a reaction showing a certain distribution o/p might have a totally different distribution when changing temperature or solvent

however, there is the rule of thumb that with not too much sterical hindrance (and no other factors like neighboring group effects involved) , you usually will get more o than p product.

regards

Ingo

[orgopete]

however, there is the rule of thumb that with not too much sterical hindrance (and no other factors like neighboring group effects involved) , you usually will get more o than p product.

To agree with the first part, anisole give the para product on acylation.

I don't try to predict o/p ratios because they can change as Ingo noted, I prefer to look them up.

[orgo814]

You would get ortho as a minor product (probably very small percentage) and the major product would be para.

[Archer]

You would get ortho as a minor product (probably very small percentage) and the major product would be para.

In my experience of electrophillic substitutions para predominates but this is only my exprience, I don't routinely nitrate aromatic compounds so I couldn't possibly comment on this particular reaction.