Poon Thomas, Sivaguru J, Franz Roberto, Jockusch Steffen, Martinez Claudia, Washington Ilyas, Adam Waldemar, Inoue Yoshihisa, Turro Nicholas J
Joint Science Department, W.M. Keck Science Center, 925 North Mills Avenue, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, California 91711, USA.
J Am Chem Soc. 2004 Sep 1;126(34):10498-9. doi: 10.1021/ja048438c.
Oxazolidinone-functionalized enecarbamates react stereoselectively with singlet oxygen to give methyldesoxybenzoin (MDB) in moderate to high enantiomeric excess. The stereochemical outcome depends on the E/Z substrate geometry, temperature, and solvent variables. The analysis of the differential activation parameters suggests a large contribution from the entropy term in determining the enantioselectivity. We demonstrate the utility of the temperature and solvent variables in determining the degree of the photochemical kinetic resolution of the enecarbamates; for example, in the photooxygenation at -70 degrees C in methanol, MDB may be obtained in methanol.
恶唑烷酮官能化的烯氨基甲酸酯与单线态氧发生立体选择性反应，以中等至高对映体过量得到甲基脱氧苯偶姻（MDB）。立体化学结果取决于E/Z底物几何构型、温度和溶剂变量。对微分活化参数的分析表明，熵项在决定对映选择性方面有很大贡献。我们证明了温度和溶剂变量在确定烯氨基甲酸酯光化学动力学拆分程度方面的效用；例如，在-70℃的甲醇中进行光氧化反应时，可以在甲醇中得到MDB。
