ORGN 348 |
| Nitrile oxides react with alkynes in the presence of catalytic Cp*RuCl(COD) to regioselectively provide 3,4-disubstitued isoxazoles in excellent yields. In contrast, the thermal cycloaddition usually results in a mixture of 3,4- and 3,5-disubstituted isomers, while the copper(I)-catalyzed reaction provides 3,5-disubstituted isoxazoles as the only products. Thus, the present Ru-catalyzed cycloaddition provides ready access to isoxazoles which are difficult to obtain by other approaches. Internal alkynes also participated in the reaction, and a variety of functional groups were compatible with these conditions. The scope of this new transformation and its possible reaction mechanism will be discussed.
|
|
Heterocycles and Aromatics, Molecular Recognition and Self Assembly
8:00 PM-10:00 PM, Tuesday, April 8, 2008 Morial Convention Center -- Hall A, Poster
Division of Organic Chemistry |
