The title compound, diethyl 25,26,27,28-tetrahydroxypentacyclo[19.3.1.1(3,7).1(9,13).1(15,19)]octacosa-1(25),3,5,7-(18),9,11,13(27),15,17,19(26),21,23-dodecaene-5,17-dicarboxylate, C34H32O8, a tetrahydroxy calix[4]arene, adopts an open-cone conformation in the solid state; this conformation is dictated by the presence of intramolecular O-H...O hydrogen bonding of the phenolic OH groups [O...O 2.673 (2)-2.708 (2) Angstrom]. The planes of the aromatic rings are inclined at 120.8 (1), 133.1 (1), 118.0 (1) and 128.5 (1)degrees to the plane of the methylene C atoms which link them. Self-inclusion occurs when the molecules assemble in pairs about inversion centres.
The title compound, diethyl 25,26,27,28-tetrahydroxypentacyclo[19.3.1.1(3,7).1(9,13).1(15,19)]octacosa-1(25),3,5,7-(18),9,11,13(27),15,17,19(26),21,23-dodecaene-5,17-dicarboxylate, C34H32O8, a tetrahydroxy calix[4]arene, adopts an open-cone conformation in the solid state; this conformation is dictated by the presence of intramolecular O-H...O hydrogen bonding of the phenolic OH groups [O...O 2.673 (2)-2.708 (2) Angstrom]. The planes of the aromatic rings are inclined at 120.8 (1), 133.1 (1), 118.0 (1) and 128.5 (1)degrees to the plane of the methylene C atoms which link them. Self-inclusion occurs when the molecules assemble in pairs about inversion centres.
The acid-catalyzed multi-step synthesis of calix[8]arene 1, which contains a regioselectively functionalized upper rim, has been investigated through the careful separation of the resulting by-products. A total of 11 types of cyclic and acyclic by-products were isolated and identified by spectral and microanalytical data. Semiempirical molecular-orbital calculations demonstrated that the synthetic
Fragmentation Reaction via an Ipso-Attack in the Multistep Synthesis of Regioselectively Functionalized Calix[8]arene
作者:Hirohito Tsue、Kazutaka Enyo、Ken-ichi Hirao
DOI:10.1021/ol006195x
日期:2000.10.1
The acid-catalyzed convergent synthesis of a calix[8]arene containing a regioselectively functionalized upper rim has been investigated through the isolation and identification of cyclic and acyclic byproducts. Theoretical calculations demonstrated that the synthetic process involves two types of reaction mechanisms, one of which leads to the favorably constructed framework, while the other causes