Synthesis and Properties of 1-Substituted 1-Boratanaphthalenes

Abstract

1,4-Dihydro-1,1-dimethyl-1-stannanaphthalene (10) has been prepared by a multistep synthesis starting from α,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 1H NMR, 11B NMR, and 13C 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 η6 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.

Reactivity of Metallocene Catalysts for Olefin Polymerization: Influence of Activator Nature and Structure

“…[181] On the other hand, the constrained geometry analog is a poor copolymerization catalyst in ethylene/1-hexene copolymerizations unlike the classical CGC, which may be due to the lack of accessibility to the metal center surrounded by bulky N,N-(diisopropylamino) groups. [182] 7 Other Types of Polymerization…”

The 9‐Borataphenanthrene Anion

“…[10,11, Thec orresponding complexes and related compounds have been applied in fields that span olefin polymerization catalysis, [14, 30-32, 48, 54] asymmetric synthesis, [55][56][57] and single-ion magnets. [51] Research has primarily focused on monocyclic systems,w ith three types of polycyclic boratabenzene-containing frameworks reported to date:1 -boratanaphthalenes, [58] 2-boratanaphthalenes, [29,38,59] and 9-borataanthracenes [33,[60][61][62] (A-C, Figure 2). Analogues of phenanthrene with ab oron atom at the 9-position are ap articularly interesting target since they contain adistinct B = Cmoiety at the 9-and 10-positions that may be capable of acting as aborataalkene in contrast to the fused polycyclic boratabenzenes that are currently known.…”

The 9‐Borataphenanthrene Anion

“…The 1 H NMR spectrum of 1 lacks the aliphatic C−H signal at 3.88 ppm for the proton at the 10‐position and features a diagnostic singlet at −0.01 ppm for the trimethylsilyl group, shifted downfield from −0.30 ppm for D . 11 B NMR spectroscopy revealed an upfield shift from 65.8 ppm for D to 40.4 ppm for 1 , consistent with boratabenzene and borataalkene species …”