ORGN 684 |
| When diastereomeric trans- and cis-2-methyl-3,4-epoxy alcohols were subjected to diethylpropynylalane cleavage conditions, two products were obtained, the 1,3-diol and the undesired 1,4-diol. Two different chelation patterns are proposed (1 or 2) in order to explain this regioselectivity. The bidentate pathway were the aluminum reagent coordinates to the alkoxy and oxirane forming a cyclic chelate and the monodentate pathway were one equivalent of the aluminum coordinate to the ether an another equivalent coordinates to the epoxide. A theoretical and experimental study was performed to distinguish these aluminum complexes. The formation of 1 was studied with 27Al NMR and ab-initio molecular calculations. When comparing the experimental 27Al NMR shift with the calculated theoretical values we found a close correlation suggesting the formation of the bidentate complex 1.
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Physical Organic Chemistry: Calculations, Mechanisms, Photochemistry, and High-Energy Species
1:00 PM-5:00 PM, Wednesday, 16 March 2005 Convention Center -- Room 11A, Oral
Division of Organic Chemistry |
