455941-88-5Relevant academic research and scientific papers
1-Ethoxy-3-trifluoromethyl-1,3-butadiene and congeners as Diels-Alder components opening an entry to functionalized (trifluoromethyl)benzenes and -pyridines
Volle, Jean-Noel,Schlosser, Manfred
, p. 1490 - 1492 (2002)
1-Ethoxy-3-trifluoromethyl-1,3-butadiene and its 2-bromo-and 2-phenyl-substituted derivatives have been prepared by Wittig methylenation of the corresponding 4-ethoxy-1,1,1-trifluoro-3-buten-2-ones, which in turn are readily accessible from trifluoroacetic acid. The electron-rich/electron-poor dienes combine smoothly with dimethyl acetylenedicarboxylate and methyl propiolate to provide trifluoromethyl-substituted phthalates (2, 6 and 10) or benzoates (3, 7, 8 and 11). Satisfactory yields [of 4-(trifluoromethyl)pyridinecarboxylic acids 4 and 12] can even be achieved with methyl cyanoformate, a less reactive dienophile, if a large excess of the dienophile is employed. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
