A one-step synthesis of dehydro[12]annulenes using palladium-catalyzed reaction of o-diiodoarenes with acetylene gas
作者:Masahiko Iyoda、Anusorn Vorasingha、Yoshiyuki Kuwatani、Masato Yoshida
DOI:10.1016/s0040-4039(98)00882-x
日期:1998.6
Hexadehydrotribenzo[12]annulene and its analogues were synthesized in a one-pot procedure by the palladium-catalyzed cross-coupling of o-diiodobenzene and its analogues with acetylene. The reaction proceeded smoothly to give the desired dehydro[12]annulenes in moderate yields.
Preferred orientations of the SO bond in methylsulphinyl derivatives of furan and thiophene: an experimental study based on 1H, 13C, and 17O NMR spectroscopy
substitution pattern. The higher degree of coplanarity is found when the methylsulphinyl group and the halogen substituent are in position 3 and 4. Two ortho substituents determine structures with large twists of the methylsulphinyl group. The chemical shifts of 1 H, 13 C and 17 O nuclei of the methylsulphinyl group and referred to spectra in solution do not evidence trends of general validity for all
摘要 用核磁共振技术在溶液中研究了与杂环呋喃和噻吩键合的甲基亚磺酰基的优选构象。甲基亚磺酰基邻位的一个卤素原子的存在决定了 SO 键在与卤素相反的方向上的取向,并且该键与环的共面程度取决于取代模式。当甲基亚磺酰基和卤素取代基位于 3 位和 4 位时,发现更高程度的共面性。两个邻位取代基决定了甲基亚磺酰基大扭曲的结构。1 H 的化学位移,甲基亚磺酰基的 13 C 和 17 O 核和参考溶液中的光谱并未证明所有被检测化合物的普遍有效性趋势,作为甲基亚磺酰基相对于环的取向的函数。这种趋势存在于相应的苯基衍生物的情况下。然而,通过检查长程 n J (C, H) 耦合常数的行为,包括甲基的碳核,连同化学位移,可以得出关于这些分子在溶液中的构象行为的结论。也证明了由介质极性引起的平衡的可能扰动。结果表明,在呋喃的 2-甲基亚磺酰基衍生物中,S0 键优先取向于 O,O-cis 方向并从环平面显着扭曲,但
Diatropicity of 3,4,7,8,9,10,13,14-Octadehydro[14]annulenes: A Combined Experimental and Theoretical Investigation
作者:Andrew J. Boydston、Michael M. Haley、Richard Vaughan Williams、John R. Armantrout
DOI:10.1021/jo020463i
日期:2002.12.1
increased from one to two to three. This decrease in annulenic ring current is manifested in the alkene proton chemical shifts (0-2 benzenes) as well as the NICS (0-3 benzenes). Comparison of isomeric thiophene-fused annulenes shows further evidence of ring current competition as these allow for observation of intermittent degrees of delocalization throughout the annulenic core. A consistent relationship