Synthesis, Structure, and Transannular pi-pi Interaction of Novel [3.3] Cyclophanes

新型环芳烷的合成、结构和跨环 pi-pi 相互作用 [3.3]

基本信息

批准号：
06453042
负责人：
SHINMYOZU Teruo
金额：
$ 4.74万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

(1) Synthesis, Structure, and Transannular pi-pi Interaction of Multibridged [3_n] cyclophanes[3_6] (1,2,3,4,5,6) cyclophane 1, which is one of the ultimate compound in the field of [3.3] cyclophane chemistry has been synthesized and characterized. We expect 1 to have the fascinating chemical and structural features ; the photochemical isomerization of 1 to propella [3_6] prismane 2 has been predicted based on semiempirical MO calculations. For the synthesis of 1, we examined a stepwise approach starting from [3_3] (1,3,5) cyclophane. The key to the successful synthesis of 1 lay in employing intramolecular aldol condensation between an acetyl group and a pseudogeminally substituted formyl group to construct an additional bridge. This reaction provided enones in very high yields and the enones were readily reduced to trimethylene bridges by way of ketones. Hexabridged ketone, however, could not be reduced by various metal hydrides, but the employment of SmI_2 in THF in the presence of 1 … More N aqueous KOH successfully gave the alcohol, which was readily reduced by LiAlH_4-AlCl_3 to give the desired 1.Electronic absorption bands of [3_n] cyclophanes (n=6,5,4,3) 1,2,3,4 and their charge transfer (CT) bands with tetracyanoethylene (TCNE) in CHCl_3 shift to longer wavelength region with the increase of the number of trimethylene bridges. These results suggest that 1-4 tend to have stronger transannular pi-pi interaction as the number of trimethylene bridges increases. The CT band of 1 (710 nm) is the longest wavelength among those of the CT complexes, of [m. n] cyclophanes and multibridged benzenophanes with TCNE.In the variable temperature ^1H NMR spectra of 1 (toluene-d_8), the energy barriers for the trimethylene bridge inversion process are estimated to be 9.8 kcal/mol. The compound 1 is sensitve to light, and the isolation and identification of the photo-product is in progress.(2) A Synthetic Study of Double-layred Annulene Containing Two 15,16-Dimethyldihydropyrene SkeletonsIn a synthesis of double-layred annulene containing two 15,16-dimethyldihydropyrene skeletons as a model compound for the study of transannular pi-pi interaction, we found that 7,15-di-t-butyl -4,12-dimethyl [2,2] metacyclophane is converted to 2,7-di-t-buty1-15,16-dimethyldihydropyrene in good yield by photo-irradiation in acetic acid. When acetic acid solution of a dimer of the cyclophane, a precursor to the desired double-layred annulene, was irradiated with a low-pressure Hg lamp, the characterictic ^1H NMR signal of the methyl protons of the desired compound was observed. The characterization of the product is in progress. Less

(1) 多桥[3_n]环芳烷[3_6] (1,2,3,4,5,6)环芳烷1的合成、结构和跨环π-π相互作用，它是[领域的终极化合物之一] 3.3]环芳化学已被合成和表征，我们期望1具有令人着迷的化学和结构特征；1到propella的光化学异构化[3_6]。棱柱烷 2 是基于半经验 MO 计算预测的。对于 1 的合成，我们研究了从 [3_3] (1,3,5) 环烷开始的逐步方法，成功合成 1 的关键在于采用分子内羟醛缩合。该反应以非常高的产率提供了烯酮，并且烯酮很容易被还原为。然而，六桥酮不能被各种金属氢化物还原，但在 1 … More N KOH 水溶液存在下，在 THF 中使用 SmI_2 成功地得到了醇，该醇很容易被 LiAlH_4- 还原。 AlCl_3 得到所需的 1. [3_n] 环芳烷 (n=6,5,4,3) 1,2,3,4 的电子吸收带随着三亚甲基桥数量的增加，它们与CHCl_3中四氰乙烯（TCNE）的电荷转移（CT）带移动到更长的波长区域。这些结果表明，随着三亚甲基数量的增加，1-4往往具有更强的跨环pi-pi相互作用。 1 (710 nm) 的 CT 谱带是 [m. n] 环芳烷和具有 TCNE 的多桥苯并芳烷的 CT 谱带中最长的波长。根据1（甲苯-d_8）的温度^1H NMR谱，估计三亚甲基桥反转过程的能垒为9.8 kcal/mol。化合物1对光敏感，光产物的分离和鉴定为： (2) 含两个15,16-二甲基二氢芘骨架的双层轮烯的合成研究以含有两个15,16-二甲基二氢芘骨架的双层轮烯作为研究跨环π-π相互作用的模型化合物，我们发现7,15-二叔丁基-4,12-二甲基[2,2]间环芳烷在乙酸中通过光照射以良好的收率转化为 2,7-二叔丁基1-15,16-二甲基二氢芘。用低压汞灯照射环芳二聚体（所需双层轮烯的前体）的乙酸溶液，观察到所需化合物的甲基质子的特征 1 H NMR 信号。该产品正在进行中。