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首页> 外文期刊>Chemistry: A European journal >Intramolecular reactions in pseudo-geminally substituted [2.2]paracyclophanes
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Intramolecular reactions in pseudo-geminally substituted [2.2]paracyclophanes

机译：伪双取代的[2.2]对环环烷中的分子内反应

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摘要

A selection of pseudo-geminally substituted [2.2]paracyclophanes, the alkynes 6, 7, 10, 11a, and 11b and the alkenes 8 and 9 were prepared for the study of intraannular reactions between functional groups in direct juxtaposition. Whereas 9 and 10 provide the corresponding cyclobutane and cyclobutene derivatives on irradiation (12 and 13, respectively), the bis-alkynes 7 and 11b do not lead to a cyclobutadiene intermediate. In the latter case the "half-closed" butadiene derivative 17 was isolated. A Paterno-Buchi reaction took place on irradiation of 8 and 6, although the oxetene intermediate 21 produced in the second example did not survive the reaction conditions (ring-opening to 22). Bromine addition to 9, 10, and 7 occurred with high stereoselectivity (formation of the dibromides 27, 30, and 33, respectively), and is rationalized by postulating the formation of the cationic intermediates 26, 29, and 32, respectively. To study the interaction of a carbocation with a facing triple bond, the alcohol 34 was prepared from 6. On acid treatment ring closure to the triply-bridged phane 38 took place, accompanied by the hydration of the triple bond to the ketoalcohol 37. In an interesting intraannular [2+3]cycloaddition reaction the bisacetylene 11a, on treatment with n-butyl lithium, provided the cyclopentadiene derivative 42. That the two triple bonds of a pseudo-geminal diacetylene can engage in a cyclization reaction leading to the cyclopentadienone complex 44 was also shown by treating 11b with iron pentacarbonyl.
机译：为研究直接并置的官能团之间的环内反应，准备了一些伪双取代的[2.2]对环环烷烃，炔烃6、7、10、11a和11b以及烯烃8和9。 9和10在辐照时分别提供相应的环丁烷和环丁烯衍生物（分别为12和13），而双炔烃7和11b不会生成环丁二烯中间体。在后一种情况下，分离出“半封闭的”丁二烯衍生物17。尽管在第二实施例中制备的氧杂环丁烯中间体21没有在反应条件下存活（开环至22），但是在8和6的照射下发生了Paterno-Buchi反应。向溴中添加9、10和7的立体选择性高（分别形成了二溴化物27、30和33），并通过分别假定阳离子中间体26、29和32的形成来合理地添加溴。为了研究碳正离子与面对的三键的相互作用，从6中制备了醇34。在酸处理过程中，三元桥连的phane 38发生了闭环反应，伴随着三键与酮醇37的水合。有趣的环内[2 + 3]环加成反应中，用正丁基锂处理的双乙炔11a提供了环戊二烯衍生物42。假双元二乙炔的两个三键可以参与环化反应，形成环戊二烯酮络合物通过用五羰基铁处理11b也显示出44。

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