14596-70-4Relevant articles and documents
A 1,5-Bifunctional Organomagnesium Reagent for the Synthesis of Disubstituted Anthracenes and Anthrones
Link, Achim,Fischer, Christian,Sparr, Christof
, p. 397 - 402 (2016/12/24)
The preparation of a 1,5-bifunctional organomagnesium alkoxide reagent by a deprotonation-magnesiation sequence is described. This reagent reacts with carboxylic acid esters to incorporate the carboxyl carbon atom of the ester into the newly formed ring. The magnesium bisalkoxide resulting from this double nucleophilic attack is subsequently transformed in situ into halogenated disubstituted anthracenes, monosubstituted anthracenes, anthrones, or 9-substituted dihydroanthracene-cis-diols by variation of the acidic workup procedures.
SRN1 reactions of aryl halides with carbanions initiated by sodium amalgam in liquid ammonia
Austin, Eduardo,Ferrayoli, Carlos G.,Alonso, Ruben A.,Rossi, Roberto A.
, p. 4495 - 4502 (2007/10/02)
The reaction of 1-chloronaphthalene with acetone (2a) and acetophenone (2b) enolate ions was initiated by sodium amalgam [Na(Hg)] in liquid ammonia giving good yields of the substitution products 3a and 3b respectively. 2-Chloroquinoline and 2-chloropyridine gave good yields of substitution product with 2b, and moderate to good yields with 2a. 4-Bromobenzophenone and 2a gave 78% of the substitution product 5. With aryl halides whose radical anions fragment fast and consequently close to the Na(Hg) surface, such as bromobenzene and p-bromoanisole, only dehalogenation products were observed. However, when benzonitrile was used as a redox catalyst, about 50% of the substitution product 6 was obtained with p-bromoanisole and 2a. However, with the more reactive carbanionic nucleophile, such as anthrone anion 4, good yields of the substitution product 7 were obtained with bromobenzene. In all these reactions neither reduction of the aromatic moiety nor the ketone functionality was observed. It is therefore suggested that Na(Hg) amalgam initiates these SRN1 reactions.
Differences in Reactivity of Stabilized Carbanions with Haloarenes in the Initiation and Propagation Steps of the SRN1 Mechanism in DMSO
Borosky, Gabriela L.,Pierini, Adriana B.,Rossi, Roberto A.
, p. 247 - 252 (2007/10/02)
The photostimulated reaction of acetone (2), acetophenone (5), and anthrone (8) enolate ions with iodobenzene (1) in DMSO gave good yields of substitution products by the SRN1 mechanism.On the contrary, the monoanions of acetylacetone, diethyl malonate, and nitromethane (10) did not react under irradiation.However, the photostimulated reaction of 1 with 10 in the presence of 2 or pinacolone enolate ions gave 1-phenyl-2-nitroethane as a substitution product.The formation of this product can be explained if one assumes that the radical anion formed in the coupling reaction of phenyl radical with 10 fragments to give benzyl radical and nitrite ion.Benzyl radical then couples with 10 to give ultimately the observed product.From competition experiments the relative reactivity determined for the coupling reaction of different anions with phenyl radicals in the propagation cycle of the SRN1 mechanism is as follows: monoanion of β dicarbonyl compounds (unreactive) a (HOMO energy) of the anions and on the change in the ? energy that takes place in the coupling reaction.With reference to the initiation step (electron transfer from the carbanion to 1), the reactivity increases as the pKa of the conjugated acid of the nucleophile increases.
