20631-84-9Relevant academic research and scientific papers
Unusual products in reactions using ethyldimesitylborane, mesityllithium, and carbonyl compounds
Kawashima, Takayuki,Yamashita, Naoko,Kannabe, Tohru,Okazaki, Renji
, p. 354 - 357 (2001)
Unusual carbonyl adducts, Mes2BCH = CHCHCH3CRR1OH, were obtained by sequential treatment of ethyldimesitylborane with mesityllithium (2BCHCH3CRR1OH. A mechanistic study was carried out.
Enantioselective Reductive Oligomerization of Carbon Dioxide into l-Erythrulose via a Chemoenzymatic Catalysis
Bontemps, Sébastien,Clapés, Pere,Desmons, Sarah,Dumon, Claire,Fauré, Régis,Grayson-Steel, Katie,Hurtado, John,Nu?ez-Dallos, Nelson,Vendier, Laure
supporting information, p. 16274 - 16283 (2021/10/12)
A cell-free enantioselective transformation of the carbon atom of CO2has never been reported. In the urgent context of transforming CO2into products of high value, the enantiocontrolled synthesis of chiral compounds from CO2would be highly desirable. Using an original hybrid chemoenzymatic catalytic process, we report herein the reductive oligomerization of CO2into C3(dihydroxyacetone, DHA) and C4(l-erythrulose) carbohydrates, with perfect enantioselectivity of the latter chiral product. This was achieved with the key intermediacy of formaldehyde. CO2is first reduced selectively by 4e-by an iron-catalyzed hydroboration reaction, leading to the isolation and complete characterization of a new bis(boryl)acetal compound derived from dimesitylborane. In an aqueous buffer solution at 30 °C, this compound readily releases formaldehyde, which is then involved in selective enzymatic transformations, giving rise either (i) to DHA using a formolase (FLS) catalysis or (ii) to l-erythrulose with a cascade reaction combining FLS and d-fructose-6-phosphate aldolase (FSA) A129S variant. Finally, the nature of the synthesized products is noteworthy, since carbohydrates are of high interest for the chemical and pharmaceutical industries. The present results prove that the cell-freede novosynthesis of carbohydrates from CO2as a sustainable carbon source is a possible alternative pathway in addition to the intensely studied biomass extraction andde novosyntheses from fossil resources.
Bonding in Barium Boryloxides, Siloxides, Phenoxides and Silazides: A Comparison with the Lighter Alkaline Earths
Carpentier, Jean-Fran?ois,Cordier, Marie,Dorcet, Vincent,Hammoud, Joanna,Kahlal, Samia,Le Coz, Erwann,Roisnel, Thierry,Saillard, Jean-Yves,Sarazin, Yann
, p. 11966 - 11982 (2021/07/16)
Barium complexes ligated by bulky boryloxides [OBR2]? (where R=CH(SiMe3)2, 2,4,6-iPr3-C6H2 or 2,4,6-(CF3)3-C6H2), siloxide
Syntheses and reductions of C-dimesitylboryl-1,2-dicarba-closo-dodecaboranes
Kahlert, Jan,B?hling, Lena,Brockhinke, Andreas,Stammler, Hans-Georg,Neumann, Beate,Rendina, Louis M.,Low, Paul J.,Weber, Lothar,Fox, Mark A.
, p. 9766 - 9781 (2015/06/08)
Two C-dimesitylboryl-1,2-dicarba-closo-dodecaboranes, 1-(BMes2)-2-R-1,2-C2B10H10 (1, R = H, 2, R = Ph), were synthesised by lithiation of 1,2-dicarba-closo-dodecaborane and 1-phenyl-1,2-dicarba-closo-dodecaborane, respectively, with n-butyllithium and subsequent reaction with fluorodimesitylborane. These novel compounds were structurally characterised by X-ray crystallography. Compounds 1 and 2 are hydrolysed on prolonged exposure to air to give mesitylene and boronic acids 1-(B(OH)2)-2-R-1,2-C2B10H10 (3, R = H, 4, R = Ph respectively). Addition of fluoride anions to 1 and 2 resulted in boryl-carborane bond cleavage to give dimesitylborinic acid HOBMes2. UV absorption bands at 318-333 nm were observed for 1 and 2 corresponding to local π-π-transitions within the dimesitylboryl groups while visible emissions at 541-664 nm with Stokes shifts of 11 920-16 170 cm-1 were attributed to intramolecular charge transfer transitions between the mesityl and cluster groups. Compound 2 was shown by cyclic voltammetry to form a stable dianion on reduction. NMR spectra for the dianion [2]2- were recorded from solutions generated by reductions of 2 with alkali metals and compared with NMR spectra from reductions of 1,2-diphenyl-ortho-carborane 5. On the basis of observed and computed 11B NMR shifts, these nido-dianions contain bowl-shaped cluster geometries. The carborane is viewed as the electron-acceptor and the mesityl group is the electron-donor in C-dimesitylboryl-1,2-dicarba-closo-dodecaboranes.
Novel Boron-Nitrogen Containing Compounds from the Reaction of Organolithiums with Complexes between Dimesitylfluoroborane and Six- or Five-membered Aza Aromatic Compounds
Okada, Keiji,Suzuki, Riho,Oda, Masaji
, p. 2069 - 2070 (2007/10/02)
Treatment of an ether solution of dimesitylfluoroborane-pyridine with organolithium reagents at -30 deg C gives 1-dimesitylboryl-2-substituted 1,2-dihydropyridines, whereas similar treatment of dimesitylfluoroborane-thiazole or 1-substituted imidazoles gi
Barriers to rotation about the B-X bonds of coordinatively unsaturated borates and thioborates R2BXR′ (X = O, S) are not measures of the relative strengths of their B=O and B=S π bonds
Ashby, Michael T.,Sheshtawy, Nader A.
, p. 236 - 243 (2008/10/08)
The molecular structures of (2,4,6-C6H2(CH3)3) 2BXCH3 (1(X=O,S)) have been determined by single-crystal X-ray crystallography. Derivative 1(X=O) crystallizes in the triclinic space group P1 with Z = 2, a = 8.155(3) ?, b = 10.230(6) ?, c = 11.328(5) ?, α = 65.62(4)°, β = 72.70(3)°, γ = 82.12(4)°, R = 0.073, and Rw = 0.083 at -90°C. Derivative 1(X=S) crystallizes in the monoclinic space group P21/c with Z = 4, a = 13.509(8) ?, b = 8.132(5) ?, c = 16.079(6) ?, β = 99.66(4)°, R = 0.067, and Rw = 0.089 at 25°C. The boron atoms adopt approximate trigonal planar geometries, and the XC moieties lie in the C2BX planes, an orientation about the B-X bond that maximizes Bpπ-Xpπ bonding. The mesitylene rings are rotated ～60° with respect to the C2BX plane, which prohibits significant Bpπ-aryl interaction. Thus, the crystal structures of 1(X=O,S) offer benchmarks for comparing discrete Bpπ-Xpπ bonds: B-O = 1.351(5) ?, B-O-C = 123.6(3)°, C-B-O-C = 173.8(3)°, C′-B-O-C = -4.0(5)°; B-S = 1.792(6) ?, B-S-C = 109.4(3)°, C-B-S-C = 175.9(4)°, C′-B-S-C = -4.3(6)°. A comparison of the B and X effective radii (calculated by assuming the B-C and X-C lengths represent single bonds) indicates that the B-O bond is stronger than the B-S bond. Ab initio molecular orbital calculations have been carried out on the model compounds H2BXH (2(X=O,S)). The geometries of 2 have been optimized at the SCF level for various rotational orientations about the B-X bonds. The ground-state geometries of 2 are analogous to those observed experimentally, with the X-H bonds lying in the trigonal planes of the boron atoms. Mirroring the dynamic behavior observed experimentally, the energy barrier found for rotation about the B-X bond of 2(X=S) is larger than that for 2(X=O). Mulliken population analysis suggests, with respect to the BH2 π-acceptor moiety, that the OH and SH groups are comparable π donors in the ground-state geometry (H-B-X-H = 0, 180°), but the OH group is a much better π donor than the SH group in the transition-state geometry (H-B-X-H = 90°). Thus the trend in the barriers to rotation is attributed to a greater stabilization of the transition state by oxygen and not a stronger Bpπ-Spπ bond in the ground state. Accordingly, rotational barriers about the B-X bonds of R2BOR′ and R2BSR′ complexes are not measures of their relative B-X π-bond strengths.
Aromatic stabilization of the triarylborirene ring system by tricoordinate boron and facile ring opening with tetracoordinate boron
Eisch, John J.,Shafii, Babak,Odom, Jerome D.,Rheingold, Arnold L.
, p. 1847 - 1853 (2007/10/02)
To remove uncertainties in the apparent C=C and B-C bond lengths of the borirene ring, as previously estimated from an X-ray crystallographic analysis of trimesitylborirene, the unsymmetrically substituted 2-(2,6-dimethylphenyl)-1,3-dimesitylborirene was
