NOVEL STRUCTURES FROM TRIS(BENZOCYCLOBUTADIENO)CYCLOHEXATRIENE - TRISCYCLOPROPANATION AND TRISOXACYCLOPROPANATION TO THE FIRST [2.1.2.1.2.1]HEXAANNULANES

Surprisingly thermally stable, the hexaannulanes 1 can be heated without decomposition to 200 °C (1a) or 180 °C (1b). They are accessible in good yields from tris(benzocyclobutadieno)cyclohexatriene by cyclopropanation with Et2Zn or by epoxidation with 3,3‐dimethyl‐1,2‐dioxacyclopropane, respectively, and were characterized by spectroscopy and X‐ray crystallography in the case of 1a for a hexakis(trimethylsilyl) derivative. (Figure Presented.) Copyright © 1995 by VCH Verlagsgesellschaft mbH, Germany