84507-41-5Relevant academic research and scientific papers
Diels-Alder Reactions with 2H-Pyran-2-ones: Reactivity and Selectivity
Effenberger, Franz,Ziegler, Thomas
, p. 1339 - 1346 (2007/10/02)
2H-Pyran-2-ones 1 react with maleic anhydride (2) in a double Diels-Alder reaction to give bicyclooct-2-ene-5,6:7,8-tetracarboxylic dianhydrides 5; the syn/syn structure was established.As expected, the reactivity of 1 was increased by electron donor substituents (OR, alkyl) and diminished by electron withdrawing substituents (CO2R).The steric influence of substituents at C-6 also decrease the reactivity of 1. - Methyl propiolate (6) and phenylacetylene (9) react with 1 to form the Diels-Alder products 7 which suffer CO2 elimination to yield methyl benzoates 8 with low and biphenyls 10 with high regioselectivity, respectively.
Reactions of 2-alkoxyfurans with nonacarbonyldiiron or dodecacarbonyltriruthenium giving binuclear vinylcarbene complexes and a 2-pyrone complex. A novel precursor for α,β-unsaturated alkylidene ligands and an unusual carbonylation of the furans
Mitsudo, Take-Aki,Ogino, Yasukazu,Komiya, Yukiatsu,Watanabe, Hiroyoshi,Watanabe, Yoshihisa
, p. 1202 - 1207 (2008/10/08)
2-Methoxyfuran reacted with nonacarbonyldiiron in diethyl ether at 35°C for 4 h to give a binuclear α,β-unsaturated alkylidene complex, hexacarbonyl(μ-3-η1-anti-(methoxycarbonyl)-η 3:η1-allyl)diiron(i;'e-i'e)(5a) and a 2-pyrone derivative, tricarbonyl(3-6-η-6-methoxy-2-pyrone)iron (6a). 2-Methoxyfuran also reacted with dodecacarbonyltriruthenium in benzene under an atmosphere of carbon monoxide at 150°C for 4 h to give a corresponding binuclear α,β-unsaturated alkylidene complex, hexacarbonyl(μ-3-η1-anti-(methoxycarbonyl)-η 3:η1-allyl)dimthenium(Ru-Ru) (10), 6-methoxy-2-pyrone (11), and dimethyl glutaconate (12). Both reactions could be explained by assuming mononuclear η3-vinylcarbene complexes as reaction intermediates.
