| Abstract
| - The alkylation of 4-methoxymethyl-γ-butyrolactone enolate with methyl chloride was studied atthe B3LYP/6-31+G* level. Conformer search of the free enolate gave 15 unique conformers within 5.39kcal/mol. The transition structures for both anti- and syn-attacks of methyl chloride on these 15 conformerswere located. In all cases, the anti-transition structures are more stable than the corresponding syn-ones.The alkylation of γ-valerolactone was studied at the MP2, B3LYP, and HF levels of theory with the 6-31+G*basis set in the presence of Li+ and dimethyl ether molecules. Basis set effects were also examined by thecomparison of the MP2 results with the 6-31+G*, 6-31+G**, and 6-311+G** basis sets in one case. Thisstudy shows that the main source of the anti-selectivity of 4-substituted γ-butyrolactones is eclipsing strainin the syn-transition structures.
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