The ortho-directing groups are usually arranged in the following order in order of their reactivity: SO2NR2 > SO2Ar > CONR2 > oxazolinyl > CONHR > CSNHR, CH2NR2 > OR > NHAr > SR > CR2O-.
3.1.2.1 Reactions with Carbonyl Compounds
Organolithium reacts with aldehydes, ketones and esters to give alcohols as organomagnesium halides (Scheme 5).
 |
Scheme 5 |
In comparison to organomagnesium halides, organolithiums are less susceptible to steric factors and react with hindered ketones to give tertiary alcohols (Scheme 6).
 |
Scheme 6 |
Primary amides undergo reaction with excess organolithium to give a nitrile. For an example, phenylacetamide reacts with 3 equiv of butyllithium to give trilithiated species, which undergoes fragmentation to give intermediate that could be hydrolyzed to afford benzonitrile (Scheme 7).
 |
Scheme 7 |
Another useful reaction with amides is the reaction of organolithium reagents with DMF to give aldehydes (Scheme 8).
 |
Scheme 8 |
Reaction of carboxylic acid with organolithium reagent gives the expected carboxylate salt, but a second equiv can add to the lithium carboxylate to afford a ketone (Scheme 9).
 |
Scheme 9 |