Ketones alpha-arylation

In the same way, the Ritleng and Nolan groups underlined the importance of the ligand in these alpha-arylation processes. By using mixed NHC-Ni pre-catalysts [(IPr)NiCl(Cp)] and [(IPr )NiCl(cin)], respectively, they developed efficient alpha-arylation processes for acyclic ketones with radical species postulated as key intermediate. 

Sulfur tetrafluoride [7783-60-0] SF, replaces halogen in haloalkanes, haloalkenes, and aryl chlorides, but is only effective (even at elevated temperatures) in the presence of a Lewis acid catalyst. The reagent is most often used in the replacement of carbonyl oxygen with fluorine (15,16). Aldehydes and ketones react readily, particularly if no alpha-hydrogen atoms are present (eg, benzal fluoride [455-31-2] from benzaldehyde), but acids, esters, acid chlorides, and anhydrides are very sluggish. However, these reactions can be catalyzed by Lewis acids (HP, BF, etc). 

Synthesis and Properties. Polyquinolines are formed by the step-growth polymerization of o-aminophenyl (aryl) ketone monomers and ketone monomers with alpha hydrogens (mosdy acetophenone derivatives). Both AA—BB and AB-type polyquinolines are known as well as a number of copolymers. Polyquinolines have often been prepared by the Friedlander reaction (88), which involves either an acid- or a base-catalyzed condensation of an (9-amino aromatic aldehyde or ketone with a ketomethylene compound, producing quinoline. Surveys of monomers and their syntheses and properties have beenpubhshed (89—91). 

LAPWORTH (BENZOIN) Condensation Condensation of two molecules of aryl aldehydes fo an alpha-hydroxy ketone catalysed by CN (via cyanohydnns). 

Ketones may be prepared by the reaction of the lithio intermediate with a nitrile (Reaction 11) (6). Nitriles possessing no alpha hydrogens work best in this reaction. Formyl derivatives of aromatics may be synthesized by treating the lithiated species with dimethylformamide (Reaction 12) (19). Carboxylic acids are readily available by carbonation of such lithio intermediates (14,16). Treatment of these lithio intermediates with aryl or alkyl isocyanates yields amides (Reaction 13) (10). 

---