Cyclopropyl Building Blocks for Organic Synthesis, 37. Synthesis and Diels—Alder Reactions of 2-Substituted 2-Cyclopropylideneacetates in Comparison with Allenecarboxylate and Ordinary Acrylates
作者:Armin de Meijere、Stephan Teichmann、Fereydoun Seyed-Mahdavi、Stephan Kohlstruk
DOI:10.1002/jlac.199619961208
日期:1996.12
Several new 2-substituted 2-cyclopropylideneacetates 1a-X (X=F, N3, SPh, OTBDMS, OTBDPS) have been prepared. Their cycloadditions and those of some previously described compounds of type 1a-X (X=H, Br, Cl) with furan (5) and/or 6,6-dimethylfulvene (7) are reported. Several of these peculiar acrylates 1a-X (X=H, Br, Cl, F, N3), as well as allenecarboxylate 1b, regular acrylate 1c, crotonate 1d, and
已经制备了几种新的2-取代的2-环亚丙基乙酸酯1a - X(X = F,N 3,SPh,OTBDMS,OTBDPS)。据报道它们的环加成以及一些先前描述的1a -X型化合物(X = H,Br,Cl)与呋喃(5)和/或6,6-二甲基富勒烯(7)的环加成。这些特殊的丙烯酸酯1a -X(X = H,Br,Cl,F,N 3)中的几种,以及烯丙基羧酸盐1b,规则丙烯酸酯1c,巴豆酸酯1d和3,3-二取代丙烯酸酯1e -X(X = H ,Cl)与呋喃(5)和6,6-二甲基富勒烯(7)在64°C下进行的两个系列竞争实验。1a -Cl和1a -Br与呋喃(5)的[2 + 4]环加成速度分别约为母体丙烯酸酯1c的16倍和二甲基富勒烯(7)的230和210倍,而烯丙基羧酸1b则快于母体丙烯酸酯1c。它们与4的反应速度仅为1c的30倍,并且3-取代的丙烯酸酯1d和1a -X(X = H,Cl)太迟钝,无法在这些条件下反应。从1a