Boryls Bound to Iron Carbonyl. Structure of a Rare Bis(boryl) Complex, Synthesis of the First Anionic Boryl, and Reaction Chemistry That Includes the Synthetic Equivalent of Boryl Anion Transfer

Abstract

The synthesis, structure, and reaction chemistry of iron carbonyl boryl complexes are described. Bis(boryl) complexes were prepared by reaction of Na2[Fe(CO)4] with chlorocatecholborane and substituted chlorocatecholboranes. An X-ray diffraction study of [Fe(CO)4(BCat*)2] (BCat* = −BO2C6H3-4-t-Bu) was performed and showed significant distortions from octahedral geometry. These bis(boryl) complexes underwent exchange reactions with alcohols, amines, and silylamides. They were converted to anionic compounds by reaction with LiN(SiMe3)2, and these anionic boryls are the first such examples. The anionic character allowed for nucleophilic substitutions. These complexes reacted with ClSnMe3 to yield a mixed boryl−stannyl compound in high yield. In contrast, reaction with methyl iodide or methyl triflate did not lead to an isolable alkylboryl complex. Instead, rapid formation of MeBCat occurred, a rare transformation that substitutes a boryl group for halide.

Boryl- and Bridging Boryleneiron Complexes from Aminodichloroboranes

“…While 1a, c show melting points of 35°C and 120°C, respectively, 1b proved to be an oil at room temperature. As might be expected, the spectroscopic data of 1aϪc in solution are to some extent related to those of the corresponding diborane (4) 11 B-NMR signals at δ ϭ 56.4 (1a), 56.9 (1b), and 59.1 (1c), which are shifted to low field with respect to the signal of Me 2 NBCl 2 at δ ϭ 30.5 [15] . For a similar boryliron complex, [CpFe(CO) 2 (Figure 1).…”

“…Interestingly, the borylene complexes of the type [η-BX{(C 5 H 5 )Mn(CO) 2 } 2 ] (X ϭ NMe 2 , Cl), undergo substitution reactions at the boron atom with preservation of the central Mn 2 B core [10] . Due to their kinetic lability [11] , however, boryl complexes generally react with cleavage of the boryl moiety [6a] [6d] [7e] [11] , regardless of the strength of the metalϪboron bond, which in certain cases was calculated to be stronger than corresponding metalϪcarbon bonds [12a] [12b] . In the course of our investigations on transition-metal complexes of boron with alternative boron-bound ligands [13a] [13b] , we report on the reactions of different aminodichloroboranes R 2 NBCl 2 with Na[(η 5 -C 5 RЈ 5 )Fe(CO) 2 ] to yield amino-substituted boryl or bridging borylene complexes of iron.…”

“…[6a] [6d] [7e] [11] , regardless of the strength of the metalϪboron bond, which in certain cases was calculated to be stronger than corresponding metalϪcarbon bonds [12a] [12b] .…”

Oxidative addition of a B—B bond by an iridium(I) complex: molecular structure of mer-cis-[Ir(PMe3)3Cl(Bcat)2]

“…[4]). The solution structure of 2 was established by IH, l 3 c { I~) , IH), and ' I B [ 'H) NMR spectroscopy, and its solid state structure was confirmed by a single-crystal X-ray diffraction study on crystals grown by layering hexane over a CH2C12 solution.…”

Lithiumboryl – ein Synthon für das nucleophile Borylanion

“…Genaue Kenntnisse über Boryl-und Bisborylkomplexe, [11][12][13][14][15] À -Anion dient. [18,19] In ähnlicher Weise ist die bei der übergangsmetallkatalysierten Hydroborierung von Alkenonen oft beobachtete Umkehrung der Chemoselektivität, d. h. die bevorzugte Addition von B-H an C=C-und nicht an C=O-Bindungen, auf eine Aktivierung der C=C-Bindungen im Verlauf der Katalyse und nicht auf die formale Übertragung eines Borylanions zurückzuführen. [20] Zusätzlich zu ihrer Bedeutung für die organische Synthese haben Organoborane in jüngster Zeit auch wegen ihrer besonderen chemischen und phy- ren.…”