ORGN 184 |
| The stereoselective synthesis of midsize 1,5-cycloalkadiynes (C7-C10) bears a void in accessibility. Although structural alteration of organic moieties with transition metals shows promise for the assembling of 1,5-cycloalkadiynes, there has been no systematic study on the subject. We report herein the stereoselective cyclization of dicobalthexacarbonyl-complexed bis-propargyl alcohols, affording, upon oxidative decomplexation, D,L- and meso-3,4-diaryl-1,5-cyclodecadiynes. The metal core enhances the stability of reaction intermediates and, due to its geometric parameters, favors the formation of the respective D,L-diastereomers (>77%). The extent to which the varying of synthetic strategies (zinc-induced/two-step, THF-mediated/one-step, on-column/in-flask), topology of substrates, the electronic nature of the substituents at the aromatic nuclei (H, i-Pr, OMe, OH) and their disposition (4-, 3,4-, 3,4,5-) affects the diastereoselectivity of the process will be presented, along with the results of molecular mechanics calculations. |
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Asymmetric Reactions and Syntheses, Metal-Mediated Reactions, Combinatorial, Parallel, and Solid-Phase Chemistry
8:00 PM-10:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster
Division of Organic Chemistry |