transfer. The intermediate [4.4]paracyclophane radicalcations 7·+ and 12·+ are apparently also localized radicalcations. The close interplanar distance between the two π-moieties, however, facilitates their mutual contacts. In 7·+, the intramolecular electron transfer becomes fast on the ESR time scale at room temperature; in 12·+ the transfer is fast over the temperature range 200−300 K.
Regiodirected substitution of [2.2]paracyclophanedienes and [2.2]paracyclophanes through tricarbonylchronium complexation
作者:Michael Stöbbe、Oliver Reiser、Thies Thiemann、Rhys G Daniels、Armin de Meijere
DOI:10.1016/s0040-4039(00)84527-x
日期:——
the corresponding 1,9-dienes are shown to undergo selective conplexation with Cr(CO)3L3-reagent on their less substitutedbenzene moiety. Lithiation/silytion of these complexes leads to arene- or bridge-substitution, respectively. An analagous behaviour is observed for the tricarbonylchromium[2.2]paracyclophane and its 1,9-diene.
显示4,7-二烷氧基[2.2]对环环烷和相应的1,9-二烯在它们较少取代的苯部分上与Cr(CO)3 L 3-试剂进行选择性络合。这些络合物的锂化/硅烷化分别导致芳烃取代或桥取代。观察到三羰基铬[2.2]对环环烷及其1,9-二烯的类似行为。
STOEBBE M.; REISER O.; THIEMANN T.; DANIELS R. G.; DE MEIJERE A., TETRAHEDRON LETT., 27,(1986) N 21, 2353-2356
作者:STOEBBE M.、 REISER O.、 THIEMANN T.、 DANIELS R. G.、 DE MEIJERE A.
DOI:——
日期:——
[2.2]Paracyclophane-4,7,12,15-tetrone, [2.2](1,4)Naphthalenophane-4,7,14,17-tetrone, and 1,4,8,11-Pentacenetetrone Radical Anions − A Comparative ESR Study
作者:Alexander R. Wartini、Jorge Valenzuela、Heinz A. Staab、Franz A. Neugebauer
Three types of tetrone radical anions in which two 1,4-benzoquinone units are connected by ethano (1·−, 2·−), [2.2]paracyclophane (3·−, 4·−), and anthracene bridges (5·−, 6·−) have been studied by ESR and ENDOR spectroscopy. The displacement of the unpaired electron over the two π moieties in the [2.2]cyclophane radical anions 1·−−4·− and the marked difference between the first and second reduction
The treatment of dimethoxy[n]paracyclophanes (n = 7–12) (5), [2]paracyclo[2]thiophenophane (13), and dimethoxy[2.2]paracyclophane (8) with CAN in MeCN–water afforded 2,4-cyclohexadien-1-ones 9, [8]paracyclophanedione 10, the ring-opened esters 11, and ketones 12. When the n value of 5 was 7, 8, or 9, rearrangement of the methylene bridge occurred and 9 was obtained as the main products. With the n value of 12, quinone 10 was the main product. Whereas, treatment of 13 with CAN afforded the ring-opened ester 14 as the sole product. These results show that formation of 9 is dependent on the strain of the paracyclophanes. Epoxide A was proposed as an intermediate of these reactions.
在甲腈-水中用 CAN 处理二甲氧基[n]对二环庚烷(n = 7-12)(5)、[2]对二环[2]噻吩烷(13)和二甲氧基[2.2]对二环庚烷(8),可得到 2,4-环己二烯-1-酮 9、[8]对二环庚二酮 10、开环酯 11 和酮 12。当 5 的 n 值为 7、8 或 9 时,亚甲基桥发生重排,主要产物为 9。当 n 值为 12 时,主要产物为醌 10。而用 CAN 处理 13 时,唯一的产物是开环酯 14。这些结果表明,9 的形成取决于对位环烷的应变。环氧化物 A 被认为是这些反应的中间产物。