Semiflexible Ribbon-type Structures via Repetitive Diels-Alder Cycloaddition. Cage Formation versus Polymerization
摘要:
Starting from various acetylenedicarboxylates (1a-e) as bis-dienophiles and [2.2](3,4)furanophane (2) as bis-diene, a series of ribbon-type oligomers (6) has been prepared via repetitive Diels-Alder reactions. Intramolecular Diels-Alder cycloaddition of 5, the smallest ''AB-type'' building block of 6, provides cage compound 7, whose structure has been determined unambiguously by crystallography. In order to avoid competitive retro-Diels-Alder reactions, high-pressure conditions have been applied. This approach provides ribbon-type polymers which contain cyclooctadiene (COD) moieties as ''semiflexible'' units.
作者:Gleiter, Rolf、Rittinger, Stefan、Langer, Heinrich
DOI:——
日期:——
Heterocyclic aromatic non-Kekule molecules. Synthesis and solution-phase chemistry of the singlet biradicals 3,4-dimethylenefuran and 3,4-dimethylenethiophene
作者:Keith J. Stone、Marc M. Greenberg、Silas C. Blackstock、Jerome A. Berson
DOI:10.1021/ja00192a025
日期:1989.5
3,4-Dimethylenefuran and 3,4-dimethylenethiophene, heterocyclic analogs of the disjoint non-Kekule hydrocarbon tetramethyleneethane
作者:Keith J. Stone、Marc M. Greenberg、Joshua L. Goodman、Kevin S. Peters、Jerome A. Berson
DOI:10.1021/ja00285a035
日期:1986.12
Molecular clips and tweezers with corannulene pincers
作者:Lesya Kobryn、William P. Henry、Frank R. Fronczek、Renata Sygula、Andrzej Sygula
DOI:10.1016/j.tetlet.2009.09.177
日期:2009.12
Application of the synthetic methodology developed in our laboratory yields molecular clips and tweezers with corannulene pincers and cyclooctadiene or cyclooctatetraene tethers. These highly nonplanar systems possess a potential for binding guest molecules of various sizes. One of the clips, bis(benzocorannulene)[a,e]cyclooctadiene, exists in a 'open' chair conformation encapsulating solvating nitrobenzene in the solid state, while it is expected to prefer an internally pi-pi stacked twist-boat conformation in the gas phase. (c) 2009 Elsevier Ltd. All rights reserved.
1,2,5,6-Tetra-exo-methylenecynclooctane and [2.2]-(2,3)- Furanophane as bis-diene components in diels-alder reactions