Chemistry of Anthracene–Acetylene Oligomers. XXI. Structures and Stereochemistry of Chiral Anthracene–Acetylene Dimers with an Intra-Annular Alkoxy Group
摘要:
通过交叉偶联反应合成了在环内位置具有甲氧基或乙氧基基团的蒽-炔环二聚物。DFT 计算表明,烷氧基烷基与平面刚性框架垂直,从而形成了手性结构。手性高效液相色谱法分离了对映体,并通过旋转光学和 CD 光谱测量鉴定了它们的手性。通过使用 TDDFT 方法对 CD 光谱进行理论计算,确定了它们的绝对立体化学性质。动力学测量显示,甲氧基和乙氧基化合物的对映体化障碍分别为 122 kJ mol-1 和 >142 kJ mol-1。这些化合物的结构和立体化学性质与环内烷基衍生物的结构和立体化学性质进行了比较。
Restricted Rotation Involving the Tetrahedral Carbon. LVI. NMR and Molecular Mechanics Studies on the Stereodynamics of 8,13-Dichloro-9-methoxy-1,4-dimethyltriptycene
作者:Gaku Yamamoto、Michinori Oki
DOI:10.1246/bcsj.58.1690
日期:1985.6
The 400 MHz 1H NMR spectrum of the title compound at −100 °C in dichloromethane revealed the presence of two isomers in a ratio of 88 : 12, which results from restricted rotation about the triptycyl–oxygen single bond. The major isomer was assigned to the ap rotamer on the basis of the low temperature 13C NMR spectrum. Dynamic NMR studies gave the activation parameters for the ap→±sc conversion: ΔH\eweq=11.9±0.5 kcal/mol (1 calth=4.184 J), ΔS\eweq=2.6±2.5 eu, ΔG\eweq200K=11.4 kcal/mol. Results of molecular mechanics calculations on the compound are discussed.
作者:Herbert O. House、Joseph A. Hrabie、Don VanDerveer
DOI:10.1021/jo00356a031
日期:1986.3
Chemistry of Anthracene–Acetylene Oligomers. XXI. Structures and Stereochemistry of Chiral Anthracene–Acetylene Dimers with an Intra-Annular Alkoxy Group
作者:Takuya Tsuya、Tetsuo Iwanaga、Shinji Toyota
DOI:10.1246/bcsj.20120251
日期:2013.1.15
Anthracene–acetylene cyclic dimers having a methoxy or an ethoxy group at the intra-annular position were synthesized by cross-coupling reactions. DFT calculations suggested that the alkoxy–alkyl groups were perpendicular to the planar rigid framework leading to a chiral structure. The enantiomers were resolved by chiral HPLC and their chiroptical properties were characterized by optical rotation and CD spectral measurements. Their absolute stereochemistries were assigned by the theoretical calculation of CD spectra by using the TDDFT method. Kinetic measurements revealed that the barriers to enantiomerization were 122 and >142 kJ mol−1 for the methoxy and ethoxy compounds, respectively. The structures and stereochemistries are compared with those of intra-annular alkyl derivatives.
通过交叉偶联反应合成了在环内位置具有甲氧基或乙氧基基团的蒽-炔环二聚物。DFT 计算表明,烷氧基烷基与平面刚性框架垂直,从而形成了手性结构。手性高效液相色谱法分离了对映体,并通过旋转光学和 CD 光谱测量鉴定了它们的手性。通过使用 TDDFT 方法对 CD 光谱进行理论计算,确定了它们的绝对立体化学性质。动力学测量显示,甲氧基和乙氧基化合物的对映体化障碍分别为 122 kJ mol-1 和 >142 kJ mol-1。这些化合物的结构和立体化学性质与环内烷基衍生物的结构和立体化学性质进行了比较。