Synthesis and Properties of 1-substituted 1-boratanaphthalenes

1,4-Dihydro-1, 1-dimethyl-1-stannanaphthalene (10) has been prepared by a multistep synthesis starting from cr,2-dibromotoluene (6). The reaction of 10 with MeBBr2 followed by LDA afforded lithium 1-methyl-1-boratanaphthalene (2a). The reaction of 10 with BCl3, followed by diisopropylamine and subsequent treatment with LDA, gave lithium N,N-diisopropyl-1-amino-1-boratanaphthalene (2c). The boratanaphthalenes have been characterized using H-1 NMR, B-11 NMR, and C-13 NMR spectroscopy. The pK(a) of the conjugate acid of 2c is close to that of indene. 2a reacts with [Cp*RuCl](4) to form Ru sandwich compound 4a, in which the boratanaphthalene is eta(6) bound to Ru. 2c reacts with Cp*ZrCl3 to form a Cp*ZrCl2 adduct 5c, in which the boratanaphthalene unit is unsymmetrically bound to Zr.