82297-19-6Relevant academic research and scientific papers
DIENOPHILIE DES OLEFINES CAPTODATIVES - VI SYNTHESES ET CYCLOADDITIONS DE DIELS-ALDER DES α-ALKYLTHIO-ACRYLATES D'ALKYLE AVEC LE CYCLOPENTADIENE: INFLUENCE DES FACTEURS STERIQUES SUR LA REACTIVITE ET SUR LA STEREOSELECTIVITE
Boucher, Jean-Luc,Stella, Lucien
, p. 3595 - 3606 (2007/10/02)
The Diels-Alder reactions of cyclopentadiene with a series of four α-alkylthio-alkyl acrylates were investigated.Although slightly slower than the reactions of unsubstituted alkyl acrylates, the spontaneous cycloadditions of these captodative olefins occur at room temperature affording adducts in excellent yield.The steric effect of the ester function is found to be more important in determining the dienophilic reactivity than the endo/exo ratios of the adducts and increase in the size of the alkylthio group reduces the endo selectivity of that group from 66-69percent (for methylthio) to 25-22percent (for tertiobutylthio group).The aluminium trichloride complexed methoxycarbonyl group leads to a very high endo-stereoselectivity (97percent) of that group.
DIENOPHILIE DES OLEFINES CAPTODATIVES-VII: CYCLOADDITIONS DE DIELS-ALDER DE L'α-METHYLTHIO-ACRYLATE DE METHYLE, REACTIONS THERMIQUES, REACTIONS CATALYSEES PAR UN ACIDE DE LEWIS ET TRANSFORMATIONS DES ADDUITS
Boucher, Jean-Luc,Stella, Lucien
, p. 3607 - 3616 (2007/10/02)
The Diels-Alder reactions of the α-methylthio methyl acrylate with simple dienes are investigated.The uncatalyzed thermal reactions proceed in high yield.With cyclic dienes they give adducts in wich the carbonyl containing substituent of the major product occupied the exo position.We have shown that with cyclopentadiene the stereoselectivity decreases with increasing temperature.In the presence of a Lewis acid catalyst, the regioselectivity is enhanced and the stereoselectivity is radically reversed.The cycloadducts are amenable to further usefull transformations which illustrate that the α-methylthio methyl acrylate can be used as a synthetic equivalent of either ketene or methoxycarbonyl-acetylene.
