Addition of the germene Mes2Ge=CR2 to 1,4-naphthoquinone yields a singular o-quinodimethane which gives Diels-Alder reactions at room temperature and reacts cleanly with oxygen to form an endoperoxide.
Germenes Mes 2 GedCR 2 1a (Mes = 2,4,6-trimethylphenyl; CR 2 = fluorenylidene) and Mes 2 GedCR 0 2 1b (CR 0 2 =2,7-di-tert-butylfluorenylidene) react with 1,4-benzoquinone and 2,3,5,6-tetramethyl-1,4-benzoquinone to give compounds 3a, 3b, and 5a, containing a 1,4-cyclohexadiene unit as central ring. Upon prolonged storage in diethyl ether or THF solution, compounds 3a and 3b undergo a double 1,3-hydrogen shift, leading to their structural isomers 4a and 4b. Theoretical calculations performed on the model compound H 2 GedCH 2 1H postulate that the first steps of its reaction with 1,4-benzoquinone are a double [2þ2] cycloaddition between the GedC and CdO double bonds, leading to a transient dispiro compound containing two oxagermetane rings, followed by its isomerization to derivative 3H. Between 1a and 9,10anthraquinone, a double [2þ4] cycloaddition is observed involving the oxygens and the ortho-carbon atoms of one adjacent aromatic ring system, to generate the dioxadigermabenzopyrene derivative 2a.
The germene Mes 2 GedCR 2 (1, CR 2 ) fluorenylidene) shows varied behavior toward nitriles. It reacts as a 1,2-dipole with t-BuCN giving a four-membered ring heterocycle, 2-aza-3germacyclobut-1-ene, as a 1,4-dipole with PhCN, leading to a six-membered ring heterocycle, 3,4-dihydro-3-germaisoquinoline, and as a base, abstracting the R-H of R′CH 2 CN to give R-cyanogermanes (R′ ) H, 2-thienyl, 2-FC 6 H 4 , 4-FC 6 H 4 ).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.