Beer Henrik, Bresien Jonas, Michalik Dirk, Rölke Anne-Kristin, Schulz Axel, Villinger Alexander, Wustrack Ronald
Institute of Chemistry, University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock, Germany.
Leibniz Institute for Catalysis, Albert-Einstein-Straße 29a, 18059 Rostock, Germany.
J Org Chem. 2020 Nov 20;85(22):14435-14445. doi: 10.1021/acs.joc.0c00460. Epub 2020 May 29.
The reaction of the singlet biradical [P(μ-NHyp)] (Hyp = hypersilyl, (MeSi)Si) with different isonitriles afforded a series of five-membered NPC heterocycles. Depending on the steric bulk of the substituent at the isonitrile, migration of a Hyp group was observed, resulting in two structurally similar but electronically very different isomers. As evidenced by comprehensive spectroscopic and theoretical studies, the heterocyclopentadiene isomer may be regarded as a rather unreactive closed-shell singlet species with one localized N═P and one C═P double bond, whereas the heterocyclopentanediyl isomer represents an open-shell singlet biradical with interesting photochemical properties, such as photoisomerization under irradiation with red light to a [2.1.0]-housane-type species.
单线态双自由基[P(μ-NHyp)]（Hyp = 超硅基，(MeSi)Si）与不同的异腈反应生成了一系列五元NPC杂环。根据异腈上取代基的空间位阻，观察到一个Hyp基团发生迁移，产生了两种结构相似但电子性质差异很大的异构体。全面的光谱和理论研究表明，杂环戊二烯异构体可被视为一种相当不活泼的闭壳单线态物种，具有一个局域化的N═P和一个C═P双键，而异环戊二烯基异构体则代表一种开壳单线态双自由基，具有有趣的光化学性质，如在红光照射下光异构化为[2.1.0]-胡桑型物种。
