对-叔丁基杯[8]芳烃与低聚乙二醇二甲苯磺酸酯的直接烷基化提供了杯状[8]冠-n,其具有取决于所用碱的性质的桥接模式。碱金属氢化物(NaH或KH)主要提供1,4-calix [8]冠冕2 n,产率高达46%,而K 2 CO 3和Cs 2 CO 3与三甘醇二甲苯磺酸盐产生1,3-冠冕4 4和其1,5-异构体5 4分别为主要产物。除NaH以外,所有碱基均形成了适量的1,2-calix [8]冠3 4。在室温下1化合物2 n –5 4的1 H NMR光谱显示了宽泛的信号,表明构象迁移受到阻碍。
作者:Corrada Geraci、Grazia M. L. Consoli、Mario Piattelli、Placido Neri
DOI:10.1135/cccc20041345
日期:——
Biscrowned calix[8]arenes were obtained by alkylation of p-tert-butylcalix[8]arene or calix[8]monocrowns with triethylene glycol ditosylate, in the presence of various bases. Of the 22 possible isomers, 1,4:2,5-, 1,3:2,5-, 1,4:2,3-, 1,4:5,8-, and 1,2:3,4-calix[8]biscrown-4 (3-7) were isolated in 7-30% yields. The presence of two crown bridges in 1,3:2,5- and 1,4:2,5-biscrown-4 (4, 5) leads to a significant rigidness of the calix[8]arene macrocycle and implies inherent chirality. The increased preorganization of calix[8]biscrowns, with respect to monocrowns, leads to significant complexing abilities for alkali cations with a marked preference for Cs+ over Na+.
Inherent chirality in calix[8]arenes exploiting the steric constraint of two intercrossing polyether chains
作者:Corrada Geraci、Mario Piattelli、Placido Neri
DOI:10.1016/0040-4039(96)01678-4
日期:1996.10
The first example of covalently linked, inherently chiral calix[8]arene, 1,4-2,5-calix[8]bis-crown-4 3, has been obtained from either 1,4-calix[8]crown-4 1 or p-tert-butylcalix[8]arene by alkylation with triethylene glycol ditosylate. The inherent chirality of 3, due to the steric constraint of the two intercrossing crown bridges, is evidenced by signal splitting in the 1H NMR spectrum after addition
共价连接的固有手性杯[8]芳烃,1,4-2,5-杯[8] bis-crown-4 3的第一个例子是从1,4-杯[8] crown-4获得的。1个或p -叔-butylcalix [8]芳烃通过用三甘醇二甲苯磺酸酯烷基化。添加两个Pirkle's试剂后,在1 H NMR光谱中发生信号分裂,这是由于两个交叉的冠桥的空间约束所致的固有手性3。
Regioselective synthesis of calix[8]crowns by direct alkylation of p-tert-butylcalix[8]arene
作者:Corrada Geraci、Mario Piattelli、Placido Neri
DOI:10.1016/0040-4039(96)00684-3
日期:1996.5
Directalkylation of p-tert-butylcalix[8]arene with oligoethylene glycol ditosylates affords calix[8]crowns-n with a bridging pattern dependent on the nature of the base used. Alkali metal hydrides (NaH or KH) afford mainly 1,4-calix[8]crowns 2n in yield up to 46%, while K2CO3 and Cs2CO3 with triethylene glycol ditosylate give the 1,3-crown 44 and its 1,5-isomer 54 as the main product, respectively
对-叔丁基杯[8]芳烃与低聚乙二醇二甲苯磺酸酯的直接烷基化提供了杯状[8]冠-n,其具有取决于所用碱的性质的桥接模式。碱金属氢化物(NaH或KH)主要提供1,4-calix [8]冠冕2 n,产率高达46%,而K 2 CO 3和Cs 2 CO 3与三甘醇二甲苯磺酸盐产生1,3-冠冕4 4和其1,5-异构体5 4分别为主要产物。除NaH以外,所有碱基均形成了适量的1,2-calix [8]冠3 4。在室温下1化合物2 n –5 4的1 H NMR光谱显示了宽泛的信号,表明构象迁移受到阻碍。
Crownedcalix[8]arenes are obtained by directalkylation of p-tert-butylcalix[8]arene (1) with poly(ethylene glycol) ditosylates in the presence of various bases. K2CO3 promotes the preferential formation of 1,3-calix[8]crowns. Cs2CO3 mainly gives the 1,5-isomers, which are selectively obtained in high yields when shorter chains are used (1,5-crown-2, 88%; 1,5-crown-3, 78%). NaH affords the 1,4-isomers