Synthesis and reactivity of cobalt boryl complexes

Abstract

The reaction between [Co(PMe3)4] and B2(4-Mecat)2 (4-Mecat = 1,2-O2-4-MeC6H3) or between [Co(PMe2Ph)4] and B2(cat)2 (cat = 1,2-O2C6H4) affords the paramagnetic Co(II) bisboryl complexes [Co(PMe3)3[B(4-Mecat)]2] and [Co(PMe2Ph)3{B(cat)]2] respectively, both of which have been structurally characterised. ESR data and preliminary diboration and boryl transfer reactivity studies are also presented. The reaction between [CoMe(PMe3)4] and B2(cat)2 affords the Co(I) monoboryl complex [Co(PMe3)4[B(cat)]].

Singular Metal Activation of Diboron Compounds

“…H 2 )) 2 ] does reveal the presence of a three-center CoB 2 interaction consistent with some degree of weak BdB bonding involving one of the Co d-orbitals and the in-phase combination of the two "empty" boron p-orbitals from the two B(O 2 C 2 H 2 ) ligands, which is consistent with these observed structural features. Interestingly, an activation of B 2 cat 2 by [Co(Me)(PMe 3 ) 4 ] through a σ-bond metathesis step could be observed resulting in the production and isolation of the Co(I) species 29 and MeBcat (Scheme 32), 121 accommodating the boryl group on the axial position. 107 The activation of B 2 pin 2 with [Co(PNP)(O t Bu)] afforded a new compound [Co(PNP)(Bcat)], which represents the first example of a square planar Co(II)-boryl complex (Scheme 33).…”

Cyclodimerisierung eines Oxoborylkomplexes durch trans‐Ligandabstraktion

“…Folglich ist der Abstand zwischen den Boratomen recht klein (184.6(10) pm), was eine mögliche elektronische Wechselwirkung andeutet. [29] In ersten Studien zeigte der Neutralkomplex 5 keine Anzeichen von Zersetzung oder Oligomerisierung, selbst nicht bei erhöhter Temperatur oder beim Bestrahlen. [20] Dagegen führte die trans-Bromid-Abstraktion unmittelbar zur Cyclodimerisierung unter Bildung der ionischen Verbindung 6.…”

Copper-Catalyzed Enantioselective Aminoboration of Styrenes with Chiral Sulfoxide Phosphine Ligand

“…Cu [3] , Co/Fe [4] , Ni [5] )催化的对碳碳不饱和键的硼化加成 反应能够方便、有效地构建烷基硼或烯基硼化合物, 其 中, 铜催化因其低毒及相对廉价的优点得到了较为广泛 的关注, 通过铜催化硼化偶联反应 [6] (硼碳化, 硼锡化和 硼胺化等)可以很好地构建多官能化烷基硼化合物, 在 有机合成中具有广泛的应用前景. α-氨基硼酯类化合物 被广泛应用在药物、天然产物和活性分子的合成中 [7] .…”