Diastereoselective Diels−Alder Reactions of α-Fluorinated α,β-Unsaturated Carbonyl Compounds: Chemical Consequences of Fluorine Substitution. 2
作者:Michael Essers、Christian Mück-Lichtenfeld、Günter Haufe
DOI:10.1021/jo015917a
日期:2002.7.1
Two alpha-fluoro alpha,beta-unsaturated carbonyl compounds, i.e., benzyl 2-fluoroacrylate (3) and 2-fluorooct-1-en-3-one (4), as well as the corresponding nonfluorinated parent compounds, were synthesized and subjected to Diels-Alder reactions with cyclopentadiene. The cycloadditions were conducted thermally, microwave-assisted, and Lewis acid-mediated (TiCl(4)). The fluorinated dienophiles exhibited
合成了两种α-氟代α,β-不饱和羰基化合物,即2-氟丙烯酸苄酯(3)和2-氟辛-1-烯-3-酮(4),以及相应的非氟化母体化合物,并对其进行了处理。与环戊二烯进行狄尔斯-阿尔德反应。环加成反应是通过热,微波辅助和路易斯酸介导的(TiCl(4))进行的。氟化的亲二烯物表现出较低的反应性和非对映异构选择性,而相应的未氟化的母体化合物选择性地内消旋地反应。DFT计算表明,氟的动力学效应决定了exo产物的立体选择性,而不是更高的热力学稳定性。