Propynal Equivalents and Diazopropyne: Synthesis of All Mono-<sup>13</sup>C Isotopomers
作者:Randal A. Seburg、Jonathan A. Hodges、Robert J. McMahon
DOI:10.1002/hlca.200800446
日期:2009.8
Mechanistic and spectroscopic investigations of reactive C3H2 hydrocarbons necessitated the preparation of diazopropyne isotopomers bearing mono‐13C substitution at each of the three unique positions. The diazo compounds and their tosylhydrazone precursors were prepared from the mono‐13C isotopomers of propynal (in the form of either the aldehyde or the diethyl acetal). The introduction of 13C‐labeling
对反应性C 3 H 2烃的力学和光谱研究使得必须制备在三个独特位置均带有单13 C取代基的重氮丙炔异位异构体。重氮化合物及其甲苯磺酰zone前体是由丙炔的单13 C异构体(以醛或二乙缩醛的形式)制得的。在丙炔的任一炔烃位置引入13 C标记,利用Corey - Fuchs程序进行链同源。
Equilibrium Structure of <i>cis</i>-Hex-3-ene-1,5-diyne and Relevance to the Bergman Cyclization
作者:Robert J. McMahon、Robert J. Halter、Ryan L. Fimmen、Robb J. Wilson、Sean A. Peebles、Robert L. Kuczkowski、John F. Stanton
DOI:10.1021/ja9934908
日期:2000.2.1
gas-phase structure determination of cis-hex-3-ene-1,5-diyne (1), the parent molecule for the Bergmancyclization reaction, has been achieved through a combination of Fourier transform microwave spectroscopy and computational quantum chemistry. The microwave spectra of seven isotopes of enediyne 1 have been observed using a pulsed-nozzle Fourier transform spectrometer. The ground-state rotational constants
通过傅里叶变换微波光谱和计算量子化学的组合,已经实现了对 cis-hex-3-ene-1,5-diyne (1)(伯格曼环化反应的母体分子)的准确气相结构测定。使用脉冲喷嘴傅里叶变换光谱仪观察到烯二炔 1 的七种同位素的微波光谱。针对振动效应校正基态旋转常数并推导出平衡结构 (Re)。平衡结构与从高级 ab initio 计算 (CCSD(T)/cc-pVTZ) 获得的平衡结构显示出极好的一致性。两种方法都证实该分子具有 C2v 对称性,炔烃单元 (C-C⋮C-H) 与线性略有偏差。这些基团相互扭曲,与它们在伯格曼环化反应期间的扭曲形成鲜明对比。C1-C6 距离 (4.32 A) 被视为控制伯格曼环化反应性的关键参数,是...