Cycloproparenes

Heuristic Chemistry—Elimination Reactions

“…The odd 1,3-elimination at aromatic spacers thus leads to fused-ring aromatics. [27] Cycloproparenes or oxirenes are available through photolytic extrusion of N 2 of 3H-indoles and 3H-pyrazoles (Scheme 4 b and e) [28] or through the Wolff rearrangement. These reactions resemble the reaction patterns for the 1,3-elimination with other spacers (Scheme 1).…”

Reactivities of germacyclopropabenzene toward some transition metal carbonyl complexes

“…Dibutylether was dried by standard methods and freshly distilled prior to use. 1 H NMR (300 MHz) and 13 C NMR (75 MHz) spectra were measured in CDCl 3 , C 2 D 2 Cl 4 , or C 6 D 6 with a JEOL JNM AL-300 spectrometer. High-resolution mass spectral data were obtained on a Jeol JMS-700 spectrometer.…”

Aryl-substituted methylidenecyclopropa[b]naphthalenes: synthesis and attempted silver(I)-mediated dimerization

“…1 and 2, [1][2][3] have continued to provide a source of fascination 4 since their discovery in 1984, 5 not least because the various derivatives have unexpected polarities, [6][7][8] fluorescence characteristics, 9 and unusual properties. 4,10,11 Recently, we described five protocols that allow for the synthesis of an extensive series of 1-aryl-and 1-diaryl-methylidene-1H-cyclopropa [b]naphthalenes, their polarities, and the linear dependence of their cycloproparenyl 13 C NMR chemical shifts upon the Hammett σ p + constant of the remote aryl substituent. 3 We also addressed conjugated and cross-conjugated cycloproparene derivatives containing cyclopentadiene and dithiole sub-units, 12 and others with simple π bonds that enhance polarity through extended conjugation.…”

“…Sterically unencumbered cycloproparenes are ring-opened by simple acids (and halogens) in what is now regarded as a highly efficient benzylation reaction that is also promoted by Ag(I). 4 The Ag(I)-mediated opening is particularly efficacious, as illustrated by its use in the characterization of 1H-cyclopropa [b]naphthalene-3,6-dione, 14 but it is its application to the dimerization of the cycloproparenes that has commanded much recent attention. [15][16][17][18] For the simple cycloproparenes, the dimerization reaction entails the dropwise addition of an anhydrous chloroform solution of the cycloproparene to a suspension of AgBF 4 (ca.…”