ORGN 481 |
Fluorophenoxycarbene inside a hemicarcerand: A bottled singlet carbene
| Xuejun Liu, Gaosheng Chu, Robert A Moss, and Ralf Warmuth. Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854 |
| Incarceration in the inner phase of a hemicarcerand is one of the most powerful approaches for the room temperature stabilization of highly reactive intermediates. The surrounding host protects the guest from dimerization or reaction with bulk phase reactants that are too large to enter the inner phase. Earlier, this approach has been applied for the room temperature stabilization of highly strained or antiaromatic reactive intermediates, such as cyclobutadiene, cycloheptatetraene, and anti-Bredt bridgehead olefins. Here, we report the first stabilization of a highly reactive electron deficient species: singlet fluorophenoxycarbene. Photolysis of hemicarceplex 2@fluorophenoxydiazirine (3) yields almost quantitatively incarcerated fluorophenoxycarbene 2@1. Whereas free 1 is a transient species in solution and rapidly dimerizes, incarcerated 1 persists for hours at room temperature and was characterized for the first time by NMR spectroscopy. The NMR properties of 1 and its intramolecular and intermolecular inner phase reactivity will be discussed. 
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Total Synthesis, Process R&D, Combinatorial, Bioorganic, Physical Organic Chemistry
8:00 PM-10:00 PM, Tuesday, August 24, 2004 Pennsylvania Convention Center -- Hall D, Poster
Sci-Mix
8:00 PM-10:00 PM, Monday, August 23, 2004 Pennsylvania Convention Center -- Hall D, Sci-Mix
Division of Organic Chemistry
The 228th ACS National Meeting, in Philadelphia, PA, August 22-26, 2004
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