470485-62-2Relevant academic research and scientific papers
Cycloaddition reactions of an acetylene-linked bis(germaethene)
Meiners, Frank,Haase, Detlev,Koch, Rainer,Saak, Wolfgang,Weidenbruch, Manfred
, p. 3990 - 3995 (2002)
3,5-Di-tert-butyl-1,2-benzoquinone reacts with the acetylene-linked bis(germaethene) Ar2Ge=C(R)-C≡C-C(R)=GeAr2, R = C6H5, Ar = 2-tBu-4,5,6-Me3C6H (4), in a [4+2] fashion to furnish the sterically crowded product 5 of 2-fold cycloaddition to the Ge=C bonds. The reaction of 4 with 1,2-dicyanoethylene proceeds differently, namely, by [2+4] cycloaddition of one of the C≡N bonds to the Ge=C and C≡C bonds, followed by a [2+2] cycloaddition of the remaining Ge=C bond to the newly formed C=C bond to give the bicyclic compound 6. An unprecedented C-H activation of a tert-butyl and an aryl C-H bond leads finally to the hexacyclic compound 8 via the tetracyclic product 7. Cyanogen gas reacts similarly by [2+4] and [2+2] cycloadditions to furnish the bicyclic compound 9. In this case, no C-H addition to the endocyclic C=N bond is observed.
