Novel Structures from Tris(benzocyclobuta-dieno)cyclohexatriene: Triscyclopropanation and Trisoxacyclopropanation to the First [2.1.2.1.2.1]Hexaannulanes

摘要

In the triangular [4]phenylene 1 ("tris(benzocyclobutadieno)-cyclohexatriene"), rho-strain and antiaromatic pi-effects combine to impose a cyclohexatrienic structure on the central ring, which manifests itself chemically in its unprecedented ring-opening to the corresponding cyclic triyne and facile all-cis-hydrogenation. We now report the direct methylenation and oxidation of the cyclohexatriene unit in 1 to give the surprisingly stable novel compounds 4 and 5. incorporating the unknown, highly strained all-m-[2.1.2.1.2.1]hexaannulane frameworks 2 and 3, respectively.