Nickel(0)‐katalysierte Dimerisierung von 1,2,3‐Cycloheptatrien: Cyclobuta[1,2:3,4]dicycloheptatetraen, ein [4]Radialen‐Derivat

Nickel(O)‐Catalyzed Dimerization of 1,2,3‐Cycloheptatriene: cyclobuta[1,2:3,4]dicyclopheptatetraene, a [4]Radialene Derivative Reaction of (7‐bromotricyclo[4.1.0.0 2,7 ]hept‐1‐yl)trimethylsilane ( 4 ) with cesium fluoride in dimethylformamide at room temperature in the presence of (Ph 3 P) 4 Ni afforded a 32% yield of the [4]radialene derivative 3 . The formation of 3 is interpreted as a Ni(0)‐catalyzed dimerization of the elusive 1,2,3‐cycloheptatriene ( 2 ), which is generated by thermal rearrangement of the highly strained tricyclo[4.1.0.0 2,7 ]hept‐1(7)‐ene ( 1 ). The X‐ray structure of 3 shows an essentially planar [4]radialene subunit.