Unsaturated heterocyclic systems. XC. Uniparticulate electrophilic addition as a probe of possible bicycloaromatic and antibicycloaromatic carbonium ion character. Reactions of chlorosulfonyl isocyanate with exocyclic methylene precursors to such cations
Ketene imminium ion (4), diphenyl ketene, tosyl isocyanate and tetracyanoethylene add selectively to the semicyclic double bond of 1. This is interpreted to result from the polarity of the semicyclic double bond in 1.
An unusual bilaterally flanked olefin; X-ray crystal structure of 5,14;7,12-bis-(o-benzeno)-6,13-ethenylidene-5,5a,6,6a,7,12,12a,13,13a,14-decahydropentacene
作者:Douglas N. Butler、Indranil Gupta、Winnie Wong Ng、Stanley C. Nyburg
DOI:10.1039/c39800000596
日期:——
Spectroscopic and chemical evidence reveals the intramolecular π–π orbital proximity in the novel Diels–Alder adducts (7) and (9); the X-raycrystalstructure of (9) is reported.
作者:Hoffmann, Reinhard W.、Riemann, Achim、Mayer, Bernhard
DOI:——
日期:——
The Putative Role of Homoconjugation in Radical Cations: Electron Transfer Photochemistry of 7-Methylenenorbornadiene and 7-Methylenequadricyclane
作者:Hengxin Weng、Xue-Mei Du、Heinz D. Roth
DOI:10.1021/ja00106a017
日期:1995.1
Photoinduced electron transfer from 7-methylenenorbornadiene, MN, and 7-methylenequadricyclane, MQ, to an excited sensitizer/acceptor in the presence of methanol generates products of several structure types. All products require nucleophilic capture of the radical cations, MN(.+) and MQ(.+), by methanol, followed by rapid rearrangements of the resulting free radicals to C-. as the key intermediate. The short lifetime of the primary products of capture is ascribed to the allylic nature of their C-4-C-5 bonds. The stereochemistry of the methoxy groups in the products indicates that the nucleophile attacks MQ(.+) exclusively from the ''exo'' face (''backside'' attack), whereas MN(.+) shows, in addition, a limited degree of attack from the ''endo'' face.