ORGN 100 |
| Studies toward the synthesis of dihydropyrans by a tandem Suzuki coupling/Michael reaction of cyclic vinylic boronic acids will be described. We have generated cyclic vinylic boronic esters through the transesterification of homoallylic alcohols and vinyl boronic esters followed by ring-closing metathesis with Grubb's catalyst. In addition, we have found that the Suzuki cross-coupling of the cyclic boronic esters with ethyl cis-3-iodoacrylate generates ethyl Z,Z-7-hydroxyenoates, which when treated with sodium hydride undergo intramolecular Michael addition reactions to form dihydropyrans. Our studies have indicated that a tandem Suzuki coupling/Michael addition is possible. While the ligand (BINAP) and electrophile (ethyl cis-3-iodoacrylate) were held constant, the palladium catalyst, base, and solvent have been varied with microwave activation to determine the best conditions for the tandem Suzuki/Michael reaction. |
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Physical Organic Chemistry, Combinatorial and Process Chemistry, New Reactions and Methodology, Peptides, Proteins and Amino Acids
8:00 PM-10:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Hall A, Poster
Sci-Mix
Division of Organic Chemistry |