Grignard and RLi: basicity vs nucleophilicity

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What would be the product from nucleophilic attack on a alcohol?
Are there any difference in electrophilic nature in amides vs ketones/aldehydes?

Hi..

1) the product I think it could be a Sn1/2....where the OH-  leaves ...but is a poor leaving group -OH...it need an acid catalysis

2) amides vs ketones /aldehydes electrophilicity

The C=O of amides is less electrophilic because the -NH2 can donate its lone pair to CO..so the carbon is a bit less electrophilic

But  for the  H-α acidity  of ketones/aldehydes vs amides?
Why RLi attack the -NH2 of amide(acid base reaction) pka=25 and NOT the H , in α to C=O..pka= 20/25?!

Thanks

Alcohols can not alkylate RLi or RMgX, you need a muck better leavinggroup and even with say R-Halogen, prefferable I, the reaction is very sluggish. If you have activated halides like Allyliodide the reaction can be fast.
The fact is that RLi and RMgX are poor Sn2-nucleophiles but attacks carbonyls very fast, but amides are much less electrophilic then aldehydes or ketones. Even though alpha-protons on aldehydes and ketones are acidic attack on the carbonyl is much faster then acid-base reaction.

What would be the product from nucleophilic attack on a alcohol?
Are there any difference in electrophilic nature in amides vs ketones/aldehydes?