The inability of the intrazeolite environment to influence the regiochemistry of addition of singlet oxygen to electron-poor olefins is reported. This divergent behavior with respect to electron-rich alkenes is rationalized with a multicomplexation model that emphasizes the importance of intrazeolite substrate-cation binding.
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http://dx.doi.org/10.1021/jo025657c | DOI Listing |
J Org Chem
March 2007
Dipartimento di Chimica Organica E. Paternò, Università degli Studi di Palermo, Viale delle Scienze, Parco d'Orleans II, Edificio 17, 90128 Palermo, Italy.
Creating a stationary fluorinated environment inside the zeolite cavity can increase the reactivity observed for intrazeolite photooxidation of alkenes. Exchanging the zeolite with fluorinated organic cations is a much more effective strategy than simply using a fluorinated solvent for slurry irradiations. Use of cations containing C-F bonds is also more efficient than use of deuterated cations for creation of a singlet oxygen friendly environment where the quenching processes are slowed down.
View Article and Find Full Text PDFJ Org Chem
December 2002
Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, USA.
The intrazeolite and solution photooxygenations of a series of sulfides have been compared. The unusual zeolite environment enhances the rates of reaction, it suppresses the Pummerer rearrangements, and it has a dramatic effect on the sulfoxide/sulfone ratio. A detailed kinetic study utilizing trapping experiments and intramolecular competition provides evidence for cation complexation to a persulfoxide intermediate as the underlying phenomenon for the unique intrazeolite behavior.
View Article and Find Full Text PDFJ Am Chem Soc
September 2002
Dipartimento di Chimica Organica E. Paternò, Università degli Studi di Palermo, Parco d' Orleans II, Italy.
The intrazeolite photooxidations of several alkenes have been examined in hexane and in perfluorohexane slurries. The ability of perfluorohexane to increase the affinity of alkenes for the interior of the zeolite was documented. The nearly identical reaction rates in the two slurry solvents are attributed to a leveling of the singlet oxygen lifetime by the zeolite framework.
View Article and Find Full Text PDFJ Org Chem
May 2002
Department of Chemistry, University of Wyoming, Laramie, WY 82071, USA.
The inability of the intrazeolite environment to influence the regiochemistry of addition of singlet oxygen to electron-poor olefins is reported. This divergent behavior with respect to electron-rich alkenes is rationalized with a multicomplexation model that emphasizes the importance of intrazeolite substrate-cation binding.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!