1,N-RADICAL IONS - PHOTOSENSITIZED (ELECTRON-TRANSFER) CARBON-CARBON BOND-CLEAVAGE - FORMATION OF 1,6-RADICAL CATIONS
1,N-RADICAL IONS - PHOTOSENSITIZED (ELECTRON-TRANSFER) CARBON-CARBON BOND-CLEAVAGE - FORMATION OF 1,6-RADICAL CATIONS
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DOI：
10.1139/v91-036
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发表时间：
1991-02-01
期刊：
影响因子：
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通讯作者：
PERROTT, AL
中科院分区：
文献类型：
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作者：
ARNOLD, DR;LAMONT, LJ;PERROTT, AL
本文研究了光敏（电子转移）辐照产生的甲基2，2-二苯基环己基醚（7）、6，6-二苯基-1，4-二氧杂螺[4.5]癸烷（8）、甲基顺式和反式-2-苯基环己基醚（9顺式和反式）和6-苯基-1，4-二氧杂螺[4.5]癸烷（10）自由基阳离子的反应性。 醚和缩醛的乙腈-甲醇（3：1）溶液，以1，4-二氰基苯（2）为电子受体，用中压汞灯通过Pyrex辐照。 二苯基衍生物7和8是反应性的; 7得到6，6-二苯基己醛二甲基缩醛（11），8得到2-甲氧基-2-（5，5-二苯基戊基）-1，3-二氧戊环（12）。 这些是预期从中间体1，6-自由基阳离子得到的产物，在环状自由基阳离子的碳-碳键断裂后形成。 单苯基衍生物9顺式和反式和10在这些辐射条件下是稳定的。 讨论了碳-碳键断裂和顺-反异构化的机理。 一个解释，构象的基础上，提供了缺乏反应性的9和10。 分子力学（MM 2）计算被用来确定9顺式和反式，和10的优选构象。
The reactivity of the radical cations of methyl 2,2-diphenylcyclohexyl ether (7), 6,6-diphenyl-1,4-dioxaspiro[4.5]decane (8), methyl cis- and trans-2-phenylcyclohexyl ether (9 cis and trans), and 6-phenyl-1,4-dioxaspiro[4.5]decane (10), generated by photosensitized (electron transfer) irradiation, has been studied. Solutions of the ethers and acetals in acetonitrile-methanol (3:1), with 1,4-dicyanobenzene (2) serving as the electron acceptor, were irradiated with a medium-pressure mercury vapour lamp through Pyrex. The diphenyl derivatives 7 and 8 were reactive; 7 gave 6,6-diphenylhexanal dimethyl acetal (11) and 8 gave 2-methoxy-2-(5,5-diphenylpentyl)-1,3-dioxolane (12). These are the products expected from the intermediate 1,6-radical cation, formed upon carbon-carbon bond cleavage of the cyclic radical cation. The monophenyl derivatives 9 cis and trans and 10 were stable under these irradiation conditions. The mechanism for the carbon-carbon bond cleavage and for the cis-trans isomerization is discussed. An explanation, based upon conformation, is offered for the lack of reactivity of 9 and 10. Molecular mechanics (MM2) calculations were used to determine the preferred conformation of 9cis and trans, and 10.