38676-25-4Relevant articles and documents
RhII-Catalyzed Intermolecular C?H Arylation of Aromatics with Diazo Quinones
Wu, Kai,Cao, Bei,Zhou, Cong-Ying,Che, Chi-Ming
supporting information, p. 4815 - 4819 (2018/03/21)
We developed an efficient synthesis of biaryls by a dirhodium(II)-catalyzed aromatic C?H arylation with diazo quinones. The new biaryl synthesis can be performed under mild and neutral conditions and without directing group chelation assistance. The reaction tolerates various functionalities and is applicable to a broad range of aromatics. The regioselectivity of the C?H arylation was often high and predictable. The synthetic utility of the method was demonstrated by the late-stage modifications of a series of pharmaceuticals and functional materials as well as a short synthesis of a transthyretin amyloid inhibitor.
Direct Observation of the Cyclopropene-Vinylcarbene Rearrangement. Matrix Isolation of Bicyclohexa-3,5-dien-2-ones
Bucher, Goetz,Sander, Wolfram
, p. 1346 - 1351 (2007/10/02)
4-Oxocyclohexa-2,5-dienylidenes 4b-g have been generated in argon matrices at 10 K by visible-light irradiation of the corresponding quinone diazides 5.Carbenes 4 have been characterized by IR and UV-vis spectroscopy and by their characteristic thermal reaction with molecular oxygen.On irradiation into the longest-wavelength absorption (420-700 nm), carbenes 4c-g rearrange to give the highly strained bicyclohexa-3,5-dien-2-ones 3c-g while 4b is photostable under the same conditions.The photochemical 4 -> 3 rearrangement is completely reversible: infrared irradiation or visible light irradiation (λ > 470 nm) of the cyclopropenes 3 lead back to triplet carbenes 4 quantitatively.In addition, several of the 1,3-bridged cyclopropenes 3 undergo a thermal rearrangement to give carbenes 4.This indicates that the highly strained cyclopropenes 3 are thermodynamically less stable than the corresponding carbenes 4 and kinetically only stabilized by a shallow energy barrier.Even under the conditions of matrix isolation at cryogenic temperatures, cyclopropenes 3 are metastable compounds.
