<i>meso</i>-Tetrahydropyranylperoxides: Molecular Structures in Solution, in the Crystal, and by DFT Calculations and Their Isomerization to the Racemate
作者:Teodor Silviu Balaban、Andreas Eichhöfer、Ion Ghiviriga、Holger Hugo、Wolfgang Wenzel
DOI:10.1021/jo026839+
日期:2003.6.1
has a similar structure both in solution and in the crystal as shown by nuclear Overhauser effects and X-ray analysis, respectively. Theoretical calculations at a density functional theory level (B3LYP/6-31G) provide insight into the stabilities of the different stereoisomers of this peroxide, accounting for the facile, acid-catalyzed isomerization from the meso form to the racemate. Peroxide 3b, which
结晶过氧化物3a是全顺式2,4,6-三甲基四氢吡喃(2a)空中过氧化的主要产物(理论上为10种)。如核Overhauser效应和X射线分析所示,它在溶液和晶体中均具有相似的结构。在密度泛函理论水平(B3LYP / 6-31G)上进行的理论计算可洞察该过氧化物的不同立体异构体的稳定性,这说明了从内消旋形式到外消旋物的易受酸催化的异构化。22种理论上可能的异构体中,过氧化物3b(即3a的2-叔丁基类似物)以相似的内消旋形式结晶。由于晶体堆积效应以及固有的(轴向)手性过氧化物“发色团”与反周平面构型略有不同,