Enolate anions, arylation

This involves an aryl carbanion/enolate anion (64), and also eCQ3 derived from the action of strong bases on HCC13 (p. 267), though the latter has only a transient existence decomposing to CC12, a highly electron-deficient electrophile that attacks the aromatic nucleus ... 

It has been shown that selective a-vinylation of enolate anions derived from 1,3-dicarbonyl compounds can be achieved by reaction with 4-/-butyl-1 -cyclohexenyl-(aryl)iodonium and 1-cyclopentenyl(aryl)iodonium tehafluoroborates without competing a-arylation, provided that the alkenyliodonium salt used bears a / -mcthoxyphcnyl, rather than phenyl, group.24... 

Aryl-A3-iodanes bearing an electron-deficient alkyl ligand such as aryl(sul-fonylmethyl)-A3-iodanes (Section 3.2.7) and aryl(perfluoroalkyl)-A3-iodanes are relatively stable. A series of (perfluoroalkyl)phenyl-A3-iodanes 96 were synthesized in good yields by treating bis(trifluoroacetoxy)-A3-iodanes with benzene in the presence of triflic acid [47]. The AModanes 96 transfer the perfluoroalkyl groups to a variety of nucleophiles with reductive elimination of iodobenzene. The nucleophiles involve Grignard reagents, alkyllithiums, enolate anions, alkenes, alkynes, trimethylsilyl enol ethers, arenes, phenols, and thiols. In these reactions, the AModane 96 serves as a source of the perfluoroalkyl cation and, in... 

Mechanistic information from these reactions points to the initial formation of a radical anion of the aromatic compound, followed by loss of halide ion (3.15) subsequent attack by a second enolate anion and electron transfer to a second molecule of aryl halide provides the substitution product, and the reaction is propagated. The operation of a chain mechanism is indicated by the observation that quantum... 

A typical reaction is the photostimulated substitution of aryl halides by ketone [121-131] (and much less efficiently aldehyde [124]) enolate anions (Scheme 5), both inter- [121-128] and intramolecularly [129-131]. The SRN1 reaction with o-bromoacetophenones is a useful method for the construction of an aromatic ring (Scheme 24) [132-133], with o-halophenylalkyl ketones for macrocycles (Scheme 25) [134], with o-haloanilines for indoles [123], with o-halobenzylamines for isoquinolines [135], and several other heterocyclic syntheses are possible [136]. 

A particularly interesting combination of allyl ligand structure and the high reactivity toward aryl halides leads to the synthesis equivalent of nucleophilic aromatic substitution by enolate anions, but under completely different conditions (Scheme 51). In this example, the 2-methoxyallyl ligand is equivalent to an acetone enolate anion, but reacts with very different functional group compatibility (no polar... 

For the reaction of lithium enolate anions of esters with I2 or CX4, see 12-5. The conversion of terminal alkynes to 1-iodo-l-alkynes was reported using Nal under electrochemical conditions. The reaction of an aryl alkyne with HInCl2/BEt3,... 

It is possible to couple metalated alkyl compounds to aryl compounds. The lithium enolate anion of an ester was coupled to an aryl halide, for example, using a palladium catalyst. ... 

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