ORGN 111 |
| Lizhi Zhu1, Gordon V. Givan1, Rachel A. Taylor2, and Robert E. Minto1. (1) Department of Chemistry & Biochemistry, Miami University, Hughes Hall 256, Miami University, Oxford, OH 45056, (2) Department of Chemistry, University of Illinois, Urbana-Champaign, Urbana, IL 61801 |
| Dimethyl disulfide (DMDS) derivatization of unsaturated fatty acids is widely used for the mass spectrometric determination of the carbon-carbon double bond position, particularly in monoenoic fatty acid methyl esters (FAMEs). When polyunsaturated FAMEs bearing an 1,4-enyne functionality (e.g., methyl crepenynate), were subjected to the DMDS-I2 procedure, 2,5-disubstituted thiophene derivatives were isolated as the major products. Methyl 6-tridecene-9-ynoate was synthesized as the model compound for the study of the reaction mechanism. Under derivatization conditions, it was found that the dialkylthiophene is formed through a regioselective insertion of a sulfur atom between the C6 and C9 positions. Use of isotopic labeling, synthesis of potential intermediates, and trapping experiments support mechanisms involving initial electrophilic addition to the alkene followed by acid-catalyzed cyclization of the thiomethyl ether, potentially via an allene. This reaction provides a new route to 2,5-disubstituted thiophenes whose synthetic scope is currently being investigated. |
|
Molecular Recognition, Combinatorial, Bioorganic
8:00 PM-10:00 PM, Sunday, March 23, 2003 Convention Center -- Hall G, Poster
Division of Organic Chemistry |