74126-52-6Relevant academic research and scientific papers
Behaviour of unsaturated methyl esters with cyclopentaneacetic acid skeleton in the presence of mild lewis acids. Alkylation versus addition and lactonization
Rǎzus, Alexandru C.,Nae, ?tefania,Stanciu, Cornel
, p. 801 - 807 (2007/10/03)
The reactions of methyl 2-and 3-cyclopentenylacetate, 2-Me and 3-Me, in the presence of AlCl3/CH3NO2 or FeCl3 in benzene or in nitromethane were studied. The major products obtained in benzene were the kinetically controlled benzene alkylation compounds (6-Me as major and trans-and cis-5-Me as minor phenylated products) and the unexpected lactone 7 and hydroxyester 8. In order to understand the pathway in which the last products are formed, we made the unsaturated esters react in the absence of the aromatic substrate, in nitromethane. There are three types of products: double bond isomerization products (1-, 2-and 3-Me), H2O and HCl addition products (8 and 9) and lactone 7. The proton traces in the reaction medium cannot explain the good yields of the two last types of products. Therefore, it seems possible that the reaction may occur in two steps, (a) in the mixture of esters and catalyst and (b) during the decomposition in aqueous HCl solution. In step (a), an advanced charge polarization takes place under the influence of the Lewis acidity of the catalyst and also of the favourable steric assistance of the oxygen nonbonding pair of electrons in carbomethoxy group. In step (b), the formed complexes react with H2O and HCl to produce the addition compounds and the lactone. The key intermediate in the formation of 8 is probable an organometallic compound, I, (represented for the ester 2-Me in Scheme 1). Its precursor is a transition state, TS1, which is formed as a result of the redistribution of the oxygen nonbonding electrons and of the πC=C electrons at the same time with the implication of the metal catalyst's vacant orbital.
REACTIONS DU TYPE FRIEDEL-CRAFTS DE CERTAINS ACIDES INSATURES SUR LE BENZENE XV. CONTROLE CINETIQUE DE LA REACTION DES ACIDES INSATURES CYCLIQUES
Razus, Alexandru C.,Arvay, Zsolt,Birzan, Liviu,Nae, Stefania
, p. 1259 - 1266 (2007/10/03)
It was studied the reaction of the cyclopentylidene- and cyclopentylacetic acids and the lactone of the cis-hydroxy-2-cyclopentaneacetic acid with the benzene in the presence of aluminium chloride complexed with nitromethane or iron(III) chloride as catalyst. In these conditions the rearrangement of the reaction products was quite limitted. The reaction products were identified and a reaction mechanism was proposed.
