The First Synthesis of a Benzoborole†
This work was supported by the Deutsche Forschungsgemeinschaft.
Graphical Abstract
The flash vacuum pyrolysis of 1-chloro-1-boraindane 1 leads with dehydrogenation to the 1-benzoborole 2. The highly reactive, antiaromatic system dimerizes regiospecifically even at low temperatures to the diboradibenzotetrahydroazulene 3. Trapping reactions with 2-butyne. DCl and CH3OD furnished products which likewise suggest intermediary occurrence of 2.