9,10‐Dimetallatriptycenes of Group 14: A Novel Synthetic Approach from <i>ortho</i>‐Phenylenemagnesium

Abstract

Abstract 9,10‐Dimetallatriptycenes of Group 14 are readily accessable by a novel synthetic approach: reaction of ortho ‐phenylenemagnesium ( 1 ) with RMCl 3 afforded 9,10‐dimethyl‐9,10‐dimetallatriptycenes ( 3 ; M = Si, Ge, Sn) or 9, 10‐dimethyl‐9‐germa‐10‐stannatriptycene ( 11 ). The reaction can even be tuned to afford unsymmetrically substituted triptycenes such as 9‐methyl‐10‐phenyl‐9,10‐digermatriptycene ( 8 ); in some of these reactions, strong indications were obtained for the intermediacy of tri‐Grignard reagents RM(2‐C 6 H 4 MgCl) 3 ( 5, 10 ). The new triptycenes were characterised by their spectral data and in the case of 3c (M = Sn) by an X‐ray crystal structure determination.