Photoisomerization of tetraethyl 6,8,15,17-tetrahydro-7H,16H-5,18[1',2']-benzeno-9,14-ethenodibenzo[a,h]cyclotetradecene-7,7,16,16-tetracarboxylate. Structure of tetraethyl 2,3,3a,7b,9,10,10a,14b-hexahydro-1H,8H-3a,7b[1',2']-benzeno-10a,14b-ethenodibenzo[a,e]dicyclopenta[c,g]cyclooctene-2,2,9,9-tetracarboxylate as its methylene chloride solvate
作者:D. H. Hua、B. Dantoing、P. D. Robinson、T. C. Qui、C. Y. Meyers
DOI:10.1107/s0108270193014064
日期:1994.7.15
The initially formed cyclophane product, tetraethyl 6,8,15,17-tetrahydro-7H,16H-5,18[1',2']-benzeno-9,14-ethenodibenzo[a,h]cyclotetradecene-7,7,16,16-tetracarboxylate (1), produced from the cyclization of 9,10-bis[2,2-di(ethoxycarbonyl)]ethyl}anthracene by treatment with sodium hydride followed by 1,4-bis(bromo-methyl)-naphthalene, was completely isomerized into its intramolecular [4pis + 4pis] cycloaddition product, tetraethyl 2,3,3a,7b,9,10,10a,14b-hexahydro-1H,8H-3a,7b[1',2']-benzeno- 10a, 14b-ethenodibenzo[a, e]dicyclo-penta[c,g]cyclooctene-2,2,9,9-tetracarboxylate (II), when passed through a silica gel column under fluorescent light. The crystal structure analysis of (II) as its methylene chloride solvate showed that the length, 1.65 (1) angstrom, of each central bond, C3a-C14b and C7b-C10a, is larger than expected, and that the five-membered rings are exceptionally puckered.