TWOFOLD BORYLATION OF BENZENE-DERIVATIVES WITH (DIISOALKYLAMINO)BORADIYL UNITS

The reaction of subvalent boron species generated by the defluorination of difluoro(dioganylamino)borane with Na/K alloy in the presence of 1,4-disubstituted benzene derivatives leads to products which contain two (diorganylamino)boradiyl units and two remaining double bonds which are located on the substituted C atoms. Compounds 5 to 8 exhibit structures based on a 2,8-diborabicyclo[3.2.1]octa-3,6-diene skeleton while 9 shows a skeleton with a 1,3a,4,6a-tetrahydroborolo[3,2-b]borole structure. The latter structure corresponds to that of 1 obtained in the same reaction with benzene. The compounds are characterized by elemental analyses and spectroscopically [MS, NMR (H-1, B-11, C-13, N-15, F-19, Si-29)]. X-ray structure analyses are presented for 1, 6, 7, 8, and 9.