Dipl.-Chem. Gernot Gabbert, Dipl.-Chem. Wolfgang Weinmann, Dr. Hans Pritzkow and Prof. Dr. Walter Siebert
The reaction of methylene-1,2-diborolane 1 a and its 3-isomer 1 b with [(C5H5)Co(C2H4)2] leads to the formation of the complexes 2 a,b, in which the previously unknown 4-boryl-1-borabutadienes 3 are stabilized as ligands. The borabutadienes 3 a,b are formed by the migration of two hydrogen atoms in 1 a,b to the exo CH2 group and into the BB bond, which is opened with the formation of a complexed BC bond. 2a, 3a: R1 = H, R3 = Me; 2b, 3b: R1 = Me, R3 = H; R2 = NiPr.