Arenes reaction with amides

Fagnou and co-workers reported on the use of a palladium source in the presence of different phosphine ligands for the intramolecular direct arylation reaction of arenes with bromides [56]. Later, they discovered that new conditions employing palladium complex 27 promoted the direct arylation of a broad range of aryl chlorides to form six- and five-membered ring biaryls including different functionalities as ether, amine, amide and alkyl (Scheme 7.11) [57]. 

Systems based solely on amidic functions are still relatively rare in the cal-ixarene literature. One of the earliest examples is based on chlorosulphonation of calix[4]arene and subsequent reaction with alkylamines, which leads to the corresponding sulphonamides 27a-d. 

Desymmetrisation by enantioselective ortholithiation has been achieved with ferrocenylcarboxamides 434,187 and also (with chiral lithium amide bases) a number of chromium-arene complexes.188 The chromium arene complex 435, on treatment with s-BuLi-(-)-sparteine, gives 436 enantioselectively, and reaction with electrophiles leads to 437. However, further treatment with r-BuLi generates the doubly lithiated species 438, in which the new organolithium centre is more reactive than the old, which still carries the (-)-sparteine ligand. Reaction of 438 with an electrophile followed by protonation therefore gives ent-431.m... 

Miscellaneous Reactions. In addition to the key reactions above, DDQ has been used for the oxidative removal of chromium, iron, and manganese from their complexes with arenes and for the oxidative formation of imidazoles and thiadia-zoles from acyclic precursors. Catal)ftic amounts of DDQ also offer a mild method for the oxidative regeneration of carbonyl compounds from acetals, which contrasts with their formation from diazo compounds on treatment with DDQ and methanol in nonpolar solvents. DDQ also provides effective catalysis for the tetrahydropyranylation of alcohols. Furthermore, the oxidation of chiral esters or amides of arylacetic acid by DDQ in acetic acid provides a mild procedure for the synthesis of chiral a-acetoxy derivatives, although the diastereoselectivity achieved so far is only 65-67%. ... 

Cook reported the iron/diphosphine-catalyzed alkylation of arene-, heteroarene-, and alkeneamides with primary alkyl halides (Eq. 19) [53] and, shortly after, the alkylation of aromatic amides with benzyl chlorides and secondary alkyl bromides (Eq. 20) [54]. The reaction with primary alkyl bromides proceeded well for aromatic, heteroaromatic, and alkenyl amides despite using phenylmagnesium bromide as a base, the reaction with benzyl chlorides proceeded well under air. As previously observed by Nakamura [28, 34], the slow addition of the Grignard reagent was crucial in order to achieve high yields, presumably because of the competing homocoupling [29]. Secondary alkyl bromides and iodides could be employed in the reaction with benzamides, but acyclic secondary alkyls underwent partial isomerization to the linear alkyl. 

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