Room Temperature Observation of p-Xylylenes by 1H NMR and Evidence for Diradical Intermediates in Their Oligomerization
Authors:
- 3 February 2006
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 71 (5) , 1784-1794
Abstract
p-Quinodimethanes (p-QDMs) are reactive molecules that have been invoked as transient intermediates in a number of reactions. Dilute solutions of benzene-based p-QDMs, p-xylylene (1), α-methyl-p-xylylene (10), and 2,5-dimethyl-p-xylylene (11) can be prepared by fluoride-induced elimination of trimethylsilyl acetate from the appropriate precursor. It has been found that these solutions are stable enough to allow these reactive p-QDMs to be observed by 1H NMR spectroscopy at room temperature. For the first time, the 13C NMR spectrum of p-QDM 1 was observed. After several hours at room temperature, these p-QDMs form dimers, trimers, and insoluble oligomers. Formation of trimers provides evidence that p-QDMs 1, 10, and 11 dimerize by a stepwise mechanism involving dimeric diradicals as intermediates.Keywords
This publication has 34 references indexed in Scilit:
- [2.2.2]paracyclophane, a novel type of metal cation complexing agent (.pi.-prismand)Journal of the American Chemical Society, 1981
- Nuclear magnetic resonance spectra of quinodimethanesJournal of the American Chemical Society, 1970
- The Chemistry of Xylylenes. VI. The Polymerization of p-Xylylene2Journal of the American Chemical Society, 1960
- The Chemistry of Xylylenes. V. The Formation of Anthracenes via Fast Flow Pyrolysis of Toluenes and Related Compounds2Journal of the American Chemical Society, 1960
- The Chemistry of Xylylenes. III. Some Reactions of p-Xylylene that Occur by Free Radical Intermediates2Journal of the American Chemical Society, 1960
- Chemistry of p-xylylene, its analogues, and polymersQuarterly Reviews, Chemical Society, 1958
- The Chemistry of p-Xylylene.1 I. The Preparation of Solutions of Pseudodiradicals2Journal of the American Chemical Society, 1957
- The pyrolysis of p‐xyleneJournal of Polymer Science, 1955
- New monomers of the quinoid type and their polymersJournal of Polymer Science, 1951
- Reduction of Organic Compounds by Lithium Aluminum Hydride. II. Carboxylic AcidsJournal of the American Chemical Society, 1947