Linear free-energy relationships between stability parameters of substituted tropylium and cyclopropenylium ions as measured by reduction rate with chromium(II), reduction potential, charge-transfer energy, and pKR values
Nine tropylium ions have been synthesized and the empirical stability parameters (i)–(iv) have been measured along with the parameters of known tropylium and cyclopropenylium ions: (I) the Cr(II)-ion reduction rate constant (k2) in 10% aqueous hydrochloric acid at 25.0°; (ii) the charge-transfer frequency (vCTmax) with pyrene in 1,2-dichloroethane; (iii) the reduction peak potential (Ered) in dichloromethane
已经合成了九个对yl离子,并测量了经验稳定性参数(i)-(iv)以及已知的对yl离子和环丙烯鎓离子的参数:(I)Cr(II)离子还原速率常数(k 2) 25.0°的10%盐酸水溶液; (ii)1,在1,2-二氯乙烷中的电荷转移频率(v CT max);(iii)在二氯甲烷或乙腈中的还原峰电位(E red);(iv)在23%的乙醇水溶液,50%的乙醇水溶液和50%的乙腈水溶液中的pK R +值。当检查了这些和先前报告的结果的线性自由能关系(LFER)(a)之间的电荷转移能量(ECT)},119.5× v CT max(cm -1),kJ mol -1和E red (96.36×E red(V),kj mol -1)};(b)在log k 2 (5.70×log k 2(1 mol -1 s -1),kJ mol -1)}与E red之间;(c)在log k 2和E CT之间,发现令人满意的相互关系。
The one-electron reduction of carbonium ions. Part 12. The conformational effect of the para-cyclopropyl group on the stability of phenyltropylium ions and on their reducibilities with chromium(II) ion
p-cyclopropylphenyltropylium ions with and without flanking methyl groups has been synthesized together with various methyl-substituted phenyltropylium ions as reference compounds. The conformational effect of the para-cyclopropyl group upon the cation stability has been studied by means of 1H n.m.r. spectroscopy, pKR+ measurements, and rate measurements of one-electron reduction with chromium(II) ion. Examination
已经合成了具有和不具有侧翼甲基的一系列对-环丙基苯基tropyliumium离子以及作为参考化合物的各种甲基取代的苯基tropyliumium离子。通过1 H nmr光谱,p K R +测量以及铬(II)离子对单电子还原的速率测量,研究了对环丙基对阳离子稳定性的构象效应。检查1 H nmr光谱和这些阳离子的p K R +值表明,由于电荷离域到对位体而产生的稳定作用-环丙基随着侧翼甲基的引入而减少。当绘制铬(II)离子还原的log k 2与未取代的m-和p-甲基-,m,m-二甲基-和m-和p-甲基-的取代基常数σ +的总和时,观察到线性自由能关系。p -环丙基- phenyltropylium离子,但登录ķ 2为p具有一个或两个侧翼甲基的β-环丙基取代的阳离子大大偏离线性相关线,反映出由于环丙基的构象变化而导致的稳定性损失。
Reactions of Alkyltropylium Ions with a Base
作者:Tetsuo Nozoe、Kazuko Takahashi、Hiroshi Yamamoto
DOI:10.1246/bcsj.42.3277
日期:1969.11
On the reaction with a base (e.g., aqueous sodium hydroxide), isopropyl- and methyl-tropylium ions afforded cycloheptatrienyl polymers with an alkylene bridge, such as IIIa and IIIb, while the t-butyltropylium ion gave a mixture of 3- and 4-t-butyltropone, which was then transformed to 4-and 5-t-butyltropolone (VIIIa and IX). The bromination of VIIIa with 3 mol of bromine in methanol gave 3,7-dibromo-4-t-butyl-2-methoxy-2,3-dihydrotropolone (XIIa). On the heating of the adduct (XIIa) at 130°C, 7-bromo-4-t-butyltropolone (XIa) was formed.
Titanium-catalyzed [6π+2π]-cycloaddition of Si-containing alkynes to bis(1,3,5-cycloheptatriene-7-yl)alkanes
作者:Vladimir A. D'yakonov、Gulnara N. Kadikova、Ramil N. Nasretdinov、Dmitry I. Kolokol'tsev、Usein M. Dzhemilev
DOI:10.1016/j.tetlet.2017.03.057
日期:2017.4
The reaction between Si-containing alkynes and bis(1,3,5-cycloheptatriene-7-yl)alkanes in the presence of the two-component catalyst Ti(acac)2Cl2-Et2AlCl, led to the selective formation of mono- and bis-adducts – 9-[4-(2,4,6-cycloheptatrienyl)alkyl]-8-alkyl(phenyl)bicyclo[4.2.1]nona-2,4,7-triene-7-yl}(trimethyl)silanes and bis(7-trimethylsilyl-8-alkyl(phenyl)bicyclo[4.2.1]nona-2,4,7-triene-7-yl)alkanes
The Tropylation of Polyhydric Phenols and the Dehydrogenation of Their Products
作者:Kazuko Takahashi
DOI:10.1246/bcsj.40.1462
日期:1967.6
polyhydric phenols, such as guaiacol, catechol, resorcinol, hydroquinone, 2, 6-dimethoxyphenol, pyrogallol and phloroglucinol, has been carried out. These polyhydric phenols were quite reactive with ethyl tropyl ether or with tropylium ion, and gave mono-, di-, or sometimes tri-tropyl derivatives. The dehydrogenation of tropylpolyhydric phenol methylethers gave stable aryltropilium ions. The methoxyphenyltropones