ORGN 542 |
| N-Vinylpyridinium and -trialkylammonium tetrafluoroborate salts have been used as dienophiles (Jung's dienophile) in Diels-Alder cycloadditions (J. Am. Chem. Soc. 1988, 110, 3965). We have recently demonstrated that they also represent a new class of electrophilic coupling partner for Pd(0)-catalyzed cross-coupling reactions. We published the first examples in the Suzuki-Miyaura reaction with a wide range of boronic acids (Org. Lett. 2007, 9, 707). In this presentation, we show that these and related salts are also effective reagents for use in other Pd-catalyzed processes, including the Stille (Scheme 1) and Sonogashira reaction manifolds, and that they give good to excellent yields of 1,6-dioxo-2,4-dienes via reductive dimerization (Scheme 2). The salts are easily prepared from activated acetylenes and various amines to form generally crystalline, air-stable, and non-hygroscopic compounds.
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Physical Organic Chemistry, Metal-Mediated Reactions, Asymmetric Reactions and Syntheses
8:00 PM-10:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Organic Chemistry |
