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+.
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