Assignment of the relative and absolute stereochemistry of two novel epoxides using NMR and DFT-GIAO calculations
作者:F.C. Moraes、E.S. Alvarenga、A.J. Demuner、V.M. Viana
DOI:10.1016/j.molstruc.2018.03.050
日期:2018.7
distinct for epoxides 9 and 10 due to W coupling, and this feature was employed to confirm the assignment of these nuclei. Besides analyses of the 2D NMR spectra, the assignments of the nuclei at the epoxide ring were also inferred from information obtained by theoretical calculations. The calculated 1H and 13C NMR chemical shifts for eight candidate structures were compared with the experimental chemical
摘要 考虑到异苯并呋喃酮的潜在生物应用,特别是作为农业化学防御剂,两种新型环氧化物 (1aR,2R,2aR,5S,5aS,6S,6aS)-5-(羟甲基)六氢-2,6-甲氧基环氧乙烷 [2,3 -f]isobenzofuran-3(1aH)-one (9), and (1aS,2S,2aR,5S,5aS,6R,6aR)-5-(hydroxymethyl)hexahydro-2,6-methanooxireno[2,3-f ]isobenzofuran-3(1aH)-one (10),是从容易获得的 D-甘露醇分六个步骤合成的。由于 W 耦合,位于自行车桥的氢的多样性对于环氧化物 9 和 10 是不同的,并且该特征用于确认这些核的分配。除了对 2D NMR 谱的分析,环氧化物环上的原子核的归属也可以从理论计算获得的信息中推断出来。通过测量平均绝对误差 (MAE) 和 DP4 统计分析,将计算出的