cas 38050-71-4, 9-METHOXY-9-BORABICYCLO[3.3.1]NONANE

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Hydroboration of carbon dioxide enabled by molecular zinc dihydrides
Neutral molecular zinc(ii) dihydrides supported by N-heterocyclic carbene ligands bearing a pendant phosphine group were synthesized and then reacted with carbon dioxide to afford zinc diformates. The zinc dihydrides were found to be active catalysts for hydroboration of carbon dioxide under mild conditions, selectively giving boryl formate, bis(boryl)acetal, or methoxy borane compounds by changing the nature of the borane reductant.
Chang, Kejian,Wang, Xiaoming,Xu, Xin
p. 7324 - 7327
(2020)
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Metal-free reduction of CO2 with hydroboranes: Two efficient pathways at play for the reduction of CO2 to methanol
Guanidines and amidines prove to be highly efficient metal-free catalysts for the reduction of CO2 to methanol with hydroboranes such as 9-borabicyclo[3.3.1]nonane (9-BBN) and catecholborane (catBH). Nitrogen bases, such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 7-methyl-1,5,7- triazabicyclo[4.4.0]dec-5-ene (Me-TBD), and 1,8-diazabicycloundec-7-ene (DBU), are active catalysts for this transformation and Me-TBD can catalyze the reduction of CO2 to methoxyborane at room temperature with TONs and TOFs of up to 648 and 33 h-1 (25°C), respectively. Formate HCOOBR2 and acetal H2C(OBR2)2 derivatives have been identified as reaction intermediates in the reduction of CO2 with R2BH, and the first C-H-bond formation is rate determining. Experimental and computational investigations show that TBD and Me-TBD follow distinct mechanisms. The N-H bond of TBD is reactive toward dehydrocoupling with 9-BBN and affords a novel frustrated Lewis pair (FLP) that can activate a CO2 molecule and form the stable adduct 2, which is the catalytically active species and can facilitate the hydride transfer from the boron to the carbon atoms. In contrast, Me-TBD promotes the reduction of CO2 through the activation of the hydroborane reagent. Detailed DFT calculations have shown that the computed energy barriers for the two mechanisms are consistent with the experimental findings and account for the reactivity of the different boron reductants.
Das Neves Gomes, Christophe,Blondiaux, Enguerrand,Thuery, Pierre,Cantat, Thibault
p. 7098 - 7106
(2014)
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Catalytic properties of nickel bis(phosphinite) pincer complexes in the reduction of CO2 to methanol derivatives
A new nickel bis(phosphinite) pincer complex [2,6-(R2PO) 2C6H3]NiCl (LRNiCl, R = cyclopentyl) has been prepared in one pot from resorcinol, ClP(C5H 9)2, NiCl2, and 4-dimethylaminopyridine. The reaction of this pincer compound with LiAlH4 produces a nickel hydride complex, which is capable of reducing CO2 rapidly at room temperature to give a nickel formate complex. X-ray structures of two related nickel formate complexes LRNiOCHO (R = cyclopentyl and isopropyl) have shown an "in plane" conformation of the formato group with respect to the coordination plane. The stoichiometric reaction of nickel formate complexes LRNiOCHO (R = cyclopentyl, isopropyl, and tert-butyl) with catecholborane has suggested that the reaction is favored by a bulky R group. LRNiOCHO (R = tert-butyl) does not react with PhSiH3 at room temperature; however, it reacts with 9-borabicyclo[3.3.1]nonane and pinacolborane to generate a methanol derivative and a boryl formate species, respectively. The catalytic reduction of CO2 with catecholborane is more effectively catalyzed by a more sterically hindered nickel pincer hydride complex with bulky R groups on the phosphorus donor atoms. The nickel pincer hydride complexes are inactive catalysts for the hydrosilylation of CO 2 with PhSiH3.
Chakraborty, Sumit,Patel, Yogi J.,Krause, Jeanette A.,Guan, Hairong
p. 30 - 34
(2012)
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A Bottleable Imidazole-Based Radical as a Single Electron Transfer Reagent
Reduction of 1,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-1H-imidazol-3-ium chloride (1) resulted in the formation of the first structurally characterized imidazole-based radical 2. 2 was established as a single electron transfer reagent by treating it with an acceptor molecule tetracyanoethylene. Moreover, radical 2 was utilized as an organic electron donor in a number of organic transformations such as in activation of an aryl-halide bond, alkene hydrosilylation, and in catalytic reduction of CO2 to methoxyborane, all under ambient temperature and pressure.
Das, Arpan,Ahmed, Jasimuddin,Rajendran,Adhikari, Debashis,Mandal, Swadhin K.
supporting information
p. 1246 - 1252
(2020/12/21)

A N-Phosphinoamidinato NHC-Diborene Catalyst for Hydroboration
The use of the N-phosphinoamidinato NHC-diborene catalyst 2 for hydroboration is described. The N-phosphinoamidine tBu2PN(H)C(Ph)= N(2,6-iPr2C6H3) was reacted with nBuLi in Et2O to afford the lithium derivative, which was then treated with B2Br4(SMe2)2 in toluene to form the N-phosphinoamidinate-bridged diborane 1. It was reacted with the N-heterocyclic carbene IMe (:C{N(CH3)C(CH3)}2) and excess potassium graphite at room temperature in toluene to give the N-phosphinoamidinato NHC-diborene compound 2. It can stoichiometrically activate ammonia-borane and carbon dioxide. It also showed catalytic capability. A 2 mol % portion of 2 catalyzed the hydroboration of carbon dioxide (CO2) with pinacolborane (HBpin) in deuterated benzene (C6D6) at 110 °C (conversion >99%), which afforded the methoxyborane [pinBOMe] (yield 97.8%, TOF 33.3 h-1) and the bis(boryl) oxide [(pinB)2O]. In addition, 5 mol % of 2 catalyzed the N-formylation of secondary and primary amines by carbon dioxide and pinacolborane to yield the N-formamides (average yield 91.6%, TOF 25.9 h-1). Moreover, 2 showed chemoselectivity toward catalytic hydroboration of carbonyl compounds. In mechanistic studies, the B= B double bond in compound 2 activated the substrates, the intermediates of which then underwent hydroboration with pinacolborane to yield the products and regenerate catalyst 2.
Fan, Jun,Mah, Jian-Qiang,Yang, Ming-Chung,Su, Ming-Der,So, Cheuk-Wai
p. 4993 - 5002
(2021/02/01)

Ph2PCH2CH2B(C8H14) and Its Formaldehyde Adduct as Catalysts for the Reduction of CO2with Hydroboranes
We study two metal-free catalysts for the reduction of CO2 with four different hydroboranes and try to identify mechanistically relevant intermediate species. The catalysts are the phosphinoborane Ph2P(CH2)2BBN (1), easily accessible in a one-step synthesis from diphenyl(vinyl)phosphine and 9-borabicyclo[3.3.1]nonane (H-BBN), and its formaldehyde adduct Ph2P(CH2)2BBN(CH2O) (2), detected in the catalytic reduction of CO2 with 1 as the catalyst but properly prepared from compound 1 and p-formaldehyde. Reduction of CO2 with H-BBN gave mixtures of CH2(OBBN)2 (A) and CH3OBBN (B) using both catalysts. Stoichiometric and kinetic studies allowed us to unveil the key role played in this reaction by the formaldehyde adduct 2 and other formaldehyde-formate species, such as the polymeric BBN(CH2)2(Ph2P)(CH2O)BBN(HCO2) (3) and the bisformate macrocycle BBN(CH2)2(Ph2P)(CH2O)BBN(HCO2)BBN(HCO2) (4), whose structures were confirmed by diffractometric analysis. Reduction of CO2 with catecholborane (HBcat) led to MeOBcat (C) exclusively. Another key intermediate was identified in the reaction of 2 with the borane and CO2, this being the bisformaldehyde-formate macrocycle (HCO2){BBN(CH2)2(Ph2P)(CH2O)}2Bcat (5), which was also structurally characterized by X-ray analysis. In contrast, using pinacolborane (HBpin) as the reductant with catalysts 1 and 2 usually led to mixtures of mono-, di-, and trihydroboration products HCO2Bpin (D), CH2(OBpin)2 (E), and CH3OBpin (F). Stoichiometric studies allowed us to detect another formaldehyde-formate species, (HCO2)BBN(CH2)2(Ph2P)(CH2O)Bpin (6), which may play an important role in the catalytic reaction. Finally, only the formaldehyde adduct 2 turned out to be active in the catalytic hydroboration of CO2 using BH3·SMe2 as the reductant, yielding a mixture of two methanol-level products, [(OMe)BO]3 (G, major product) and B(OMe)3 (H, minor product). In this transformation, the Lewis adduct (BH3)Ph2P(CH2)2BBN was identified as the resting state of the catalyst, whereas an intermediate tentatively formulated as the Lewis adduct of compound 2 and BH3 was detected in solution in a stoichiometric experiment and is likely to be mechanistically relevant for the catalytic reaction.
Ramos, Alberto,Anti?olo, Antonio,Carrillo-Hermosilla, Fernando,Fernández-Galán, Rafael
supporting information
p. 9998 - 10012
(2020/07/24)

Transforming atmospheric CO2 into alternative fuels: A metal-free approach under ambient conditions
This work demonstrates the first-ever completely metal-free approach to the capture of CO2 from air followed by reduction to methoxyborane (which produces methanol on hydrolysis) or sodium formate (which produces formic acid on hydrolysis) under ambient conditions. This was accomplished using an abnormal N-heterocyclic carbene (aNHC)-borane adduct. The intermediate involved in CO2 capture (aNHC-H, HCOO, B(OH)3) was structurally characterized by single-crystal X-ray diffraction. Interestingly, the captured CO2 can be released by heating the intermediate, or by passing this compound through an ion-exchange resin. The capture of CO2 from air can even proceed in the solid state via the formation of a bicarbonate complex (aNHC-H, HCO3, B(OH)3), which was also structurally characterized. A detailed mechanism for this process is proposed based on tandem density functional theory calculations and experiments.
Chandra Sau, Samaresh,Bhattacharjee, Rameswar,Hota, Pradip Kumar,Vardhanapu, Pavan K.,Vijaykumar, Gonela,Govindarajan,Datta, Ayan,Mandal, Swadhin K.
p. 1879 - 1884
(2019/02/12)

Method for Preparing Methoxyboranes and for Producing Methanol
The present disclosure relates to a method for preparing methoxyboranes by dismutation of formic acid or at least one of the derivatives thereof or a mixture of formic acid and at least one of the derivatives thereof, in the presence of an organoborane, and optionally an organic or inorganic base.
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Paragraph 0192; 0194; 0195; 0196

(2018/12/04)

PROCESS FOR PREPARING METHANOL FROM CARBON DIOXIDE
The present invention relates to the field of chemical sciences. The present invention generally relates to a simple, economic and effective process for the conversion of carbon dioxide to methanol in the presence of carbenes or their derivatives/adducts, under mild reaction conditions. Further, said method does not require use of toxic metals/compounds for carrying out the conversion of carbon dioxide to methanol, unlike methods of the prior art.
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(2018/05/24)

Carbodiimides as catalysts for the reduction of CO2 with boranes
Carbodiimides catalyse the reduction of CO2 with H-BBN or BH3·SMe2 to give either mixtures of CH2(OBBN)2 and CH3OBBN or (MeOBO)3 and B(OMe)3 under mild conditions (25-60 °C, 1 atm CO2). Stoichiometric reactions and theoretical calculations were performed to unveil the mechanism of these catalytic processes.
Ramos, Alberto,Anti?olo, Antonio,Carrillo-Hermosilla, Fernando,Fernández-Galán, Rafael,Rodríguez-Diéguez, Antonio,García-Vivó, Daniel
supporting information
p. 4700 - 4703
(2018/05/22)

Zwitterionic indenylammonium with carbon-centred reactivity towards reversible CO2 binding and catalytic reduction
We report the synthesis and characterization of a zwitterionic indenylammonium compound and its carbon-centred reactivity towards reversible CO2 binding at ambient temperature through its formal insertion into a C-H bond as well as the catalytic hydroboration of CO2 to methanol derivatives.
Yang, Yanxin,Yan, Linfan,Xie, Qinyu,Liang, Qiuming,Song, Datong
supporting information
p. 2240 - 2245
(2017/03/20)

Pyridine-decorated carbon nanotubes as a metal-free heterogeneous catalyst for mild CO2 reduction to methanol with hydroboranes
Pyridine decorated multi-walled carbon nanotubes (NPy-MW) have been successfully employed as a catalyst for the reduction of carbon dioxide to methyl borinate (R2BO-CH3) in the presence of 9-borabicyclo[3.3.1]nonane. NPy-MW represents the first example of a heterogeneous, metal-free and durable catalyst for CO2 hydroboration to methanol. A mechanistic cycle has been proposed on the basis of targeted blank experiments and a quantum chemical study, highlighting the non-innocent role played by the nanotube carrier in the final NPy-MW catalytic performance.
Tuci,Rossin,Luconi,Pham-Huu,Cicchi,Ba,Giambastiani
p. 5833 - 5837
(2017/12/26)

Metal-free disproportionation of formic acid mediated by organoboranes
In the presence of dialkylboranes, formic acid can be converted to formaldehyde and methanol derivatives without the need for an external reductant. This reactivity, in which formates serve as the sole carbon and hydride sources, represents the first exam
Chauvier, Clément,Thuéry, Pierre,Cantat, Thibault
p. 5680 - 5685
(2016/09/04)

Complexes of the tripodal phosphine ligands PhSi(XPPh2)3 (X = CH2, O): Synthesis, structure and catalytic activity in the hydroboration of CO2
The coordination chemistry of Fe2+, Co2+ and Cu+ ions was explored with the triphosphine and triphosphinite ligands PhSi{CH2PPh2}3 (1) and PhSi{OPPh2}3 (2), so as to evaluate the impact of the electronic properties of the tripodal phosphorus ligands on the structure and reactivity of the corresponding complexes. The synthesis and characterization of the complexes [Fe(κ3-PhSi{CH2PPh2}3)(MeCN)3][OTf]2 (3) (OTf = O3SCF3), [Fe(κ3-PhSi{OPPh2}3)(MeCN)3][OTf]2 (3′), [Co(κ2-PhSi{CH2PPh2}3)Cl2] (4), [Co(κ3-PhSi{OPPh2}3)Cl2] (4′), [Cu(κ3-PhSi{CH2PPh2}3)Br] (5) and [Cu(κ3-PhSi{OPPh2}3)I] (5′) were carried out. The crystal structures of 3, 3′, 4, 4′, and of the solvates 5·3THF and 5′·THF are reported. Complexes 3-5′ were shown to promote the catalytic hydroboration of CO2 with (9-BBN)2 (9-BBN = 9-borabicyclo[3.3.1]nonane). While the iron and cobalt complexes of the triphosphine 1 are more active than the analogous complexes with 2, the opposite trend is observed with the copper catalysts. Overall, the copper catalysts 5 and 5′ are both more reactive and more selective than the Fe and Co catalysts, enabling the formation of the acetal H2C(OBBN)2 with a high molar ratio of H2C(OBBN)2 : CH3OBBN up to 92 : 8.
Aloisi, Alicia,Berthet, Jean-Claude,Genre, Caroline,Thuéry, Pierre,Cantat, Thibault
p. 14774 - 14788
(2016/09/28)

METHOD FOR PREPARING OXYBORANE COMPOUNDS
A method for preparing oxyborane compounds of formula (I): using carbon dioxide, and the use of the oxyborane compounds obtained in this way for preparing methane derivatives, in particular oxygenated, halogenated or amino derivatives of methane. The methane derivatives obtained in this way can then be used in the production of vitamins, pharmaceutical products, glues, acrylic fibres and synthetic leathers, pesticides, and fertilisers, for example. Also provided is a method for producing vitamins, pharmaceutical products, glues, acrylic fibres, synthetic leathers, pesticides, and fertilisers, for example, including a step of preparing methane derivatives, in particular oxygenated, halogenated or amino derivatives of methane, from oxyborane compounds obtained by the method according to the invention. Further provided is a method of preparing labelled oxyborane compounds and the use of same.
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Paragraph 0136; 0137; 0138; 0139

(2016/03/14)

Synergistic effects in ambiphilic phosphino-borane catalysts for the hydroboration of CO2
The benefit of combining both a Lewis acid and a Lewis base in a catalytic system has been established for the hydroboration of CO2, using ferrocene-based phosphine, borane and phosphino-borane derivatives.
Tlili, Anis,Voituriez, Arnaud,Marinetti, Angela,Thuéry, Pierre,Cantat, Thibault
supporting information
p. 7553 - 7555
(2016/07/06)

Implications of CO2 Activation by Frustrated Lewis Pairs in the Catalytic Hydroboration of CO2: A View Using N/Si+ Frustrated Lewis Pairs
A series of base-stabilized silylium species were synthesized and their reactivity toward CO2 explored, yielding the characterization of a novel N/Si+ FLP-CO2 adduct. These silicon species are active catalysts in the hydroboration of CO2 to the methoxide level with 9-BBN, catecholborane (catBH), and pinacolborane (pinBH). Both experiments and DFT calculations highlight the role of the FLP-CO2 adduct in the catalysis. Depending on the nature of the hydroborane reductant, two distinct mechanisms have been unveiled. While 9-BBN and catBH are able to reduce an intermediate FLP-CO2 adduct, the hydroboration of CO2 with pinBH follows a different and novel path where the B-H bond is activated by the silicon-based Lewis acid catalyst. In these mechanisms, the formation of a highly stabilized FLP-CO2 adduct is found detrimental to the kinetics of the reaction.
Von Wolff,Lefèvre,Berthet,Thuéry,Cantat
p. 4526 - 4535
(2016/07/12)

Metal-Free Reduction of CO2to Methoxyborane under Ambient Conditions through Borondiformate Formation
An abnormal N-heterocyclic carbene (aNHC) based homogeneous catalyst has been used for the reduction of carbon dioxide to methoxyborane in the presence of a range of hydroboranes under ambient conditions and resulted in the highest turnover number of 6000. A catalytically active reaction intermediate, [aNHC-H?9BBN(OCOH)2] was structurally characterized and authenticated by NMR spectroscopy. A detailed mechanistic cycle of this catalytic process via borondiformate formation has been proposed from tandem experimental and computational experiments.
Sau, Samaresh Chandra,Bhattacharjee, Rameswar,Vardhanapu, Pavan K.,Vijaykumar, Gonela,Datta, Ayan,Mandal, Swadhin K.
supporting information
p. 15147 - 15151
(2016/11/25)

Copper-Catalyzed γ-Selective and Stereospecific Allylic Cross-Coupling with Secondary Alkylboranes
The scope of the copper-catalyzed coupling reactions between organoboron compounds and allylic phosphates is expanded significantly by employing triphenylphosphine as a ligand for copper, allowing the use of secondary alkylboron compounds. The reaction proceeds with complete γ-E-selectivity and preferential 1,3-syn stereoselectivity. The reaction of γ-silicon-substituted allylic phosphates affords enantioenriched α-stereogenic allylsilanes.
Yasuda, Yuto,Nagao, Kazunori,Shido, Yoshinori,Mori, Seiji,Ohmiya, Hirohisa,Sawamura, Masaya
p. 9666 - 9670
(2015/06/30)

Organocatalysts with carbon-centered activity for CO2 reduction with boranes
We report two organocatalysts for CO2 hydroboration to methylborylethers, which upon hydrolysis can produce methanol. These organocatalysts feature carbon-centered reversible CO2 binding, broad borane scopes, and high catalytic activities.
Yang, Yanxin,Xu, Maotong,Song, Datong
supporting information
p. 11293 - 11296
(2015/07/07)

Iron-catalyzed reduction of CO2 into methylene: Formation of C-N, C-O, and C-C bonds
We report herein the use of the (dihydrido)iron catalyst, Fe(H)2(dmpe)2, for the selective reduction of CO2 into either bis(boryl)acetal or methoxyborane depending on the hydroborane used as a reductant. In a one-pot two-step procedure, the in situ generated bis(boryl)acetal was shown to be a reactive and versatile source of methylene to create new C-N but also C-O and C-C bonds.
Jin, Guanghua,Werncke, C. Gunnar,Escudié, Yannick,Sabo-Etienne, Sylviane,Bontemps, Sébastien
supporting information
p. 9563 - 9566
(2015/08/18)

Carbon Dioxide Reduction to Methylamines under Metal-Free Conditions
The first metal-free catalysts are reported for the methylation of amines with carbon dioxide. Proazaphosphatrane superbases prove to be highly active catalysts in the reductive functionalization of CO2, in the presence of hydroboranes. The new methodology enables the methylation of N-H bonds in a wide variety of amines, including secondary amines, with increased chemoselectivity. Organocatalysis: Proazaphosphatrane superbases prove to be highly active catalysts in the reductive functionalization of CO2, in the presence of hydroboranes. The new method makes possible the methylation of N-H bonds in a wide variety of amines, including secondary amines (see picture), with increased chemoselectivity.
Blondiaux, Enguerrand,Pouessel, Jacky,Cantat, Thibault
supporting information
p. 12186 - 12190
(2016/02/23)

Pincer-ligated nickel hydridoborate complexes: The dormant species in catalytic reduction of carbon dioxide with boranes
Nickel pincer complexes of the type [2,6-(R2PO) 2C6H3]NiH (R = tBu, 1a; R = iPr, 1b; R = cPe, 1c) react with BH3·THF to produce borohydride complexes [2,6-(R2/su
Chakraborty, Sumit,Zhang, Jie,Patel, Yogi J.,Krause, Jeanette A.,Guan, Hairong
p. 37 - 47
(2013/02/25)

Frustrated lewis pair inspired carbon dioxide reduction by a ruthenium tris(aminophosphine) complex
Frustrating ruthenium: The ruthenium complex 1 is shown to bind carbon dioxide or aldehyde in a manner similar to a frustrated Lewis pair. Compound 2 catalyzes the reduction of CO2 in the presence of pinacolborane (HBpin), yielding MeOBpin and O(Bpin)2 (see picture; Ru red, P orange, N green, O light red, C black). Copyright
Sgro, Michael J.,Stephan, Douglas W.
supporting information
p. 11343 - 11345
(2013/01/15)

Hydroboration of Disilyne RSi≡SiR (R = SiiPr[CH(SiMe 3)2]2), Giving Boryl-Substituted Disilenes
The reaction of 1,1,4,4-tetrakis[bis(trimethylsilyl)methyl]-1,4- diisopropyltetrasila-2-yne (1) with hydroboranes afforded boryl-substituted disilenes R(R2B)Si=SiHR 3a and 3b (R = SiiPr[CH(SiMe 3)2]2, R2B = 9-borabicyclo[3.3.1] nonan-9-yl (3a), catecholboryl (3b)). Spectroscopic and X-ray crystallographic analyses of 3a and 3b showed that 3a has a nearly coplanar arrangement of the Si=Si double bond and the boryl group, allowing π-conjugation between them, whereas 3b, with a markedly twisted arrangement, exhibits no such conjugation. Theoretical calculations suggest that π-conjugation between the π-orbital of the Si=Si double bond and the vacant 2p-orbital on the boron atom is markedly influenced by the dihedral angle between the Si=Si double-bond plane and boryl group plane.
Takeuchi, Katsuhiko,Ichinohe, Masaaki,Sekiguchi, Akira
p. 2044 - 2050
(2011/06/18)

The THF-9-Sodiooxy-9-borabicyclononane Tetramer
The thermolysis of Na (2), prepared from 9-Et-9-BBN (1) and NaOH, leads at about 100 deg C in the presence of NaHBEt3 as catalyst to ethane and the solid NaOBC8H14 (3), which crystallizes with one mole THF as the tetrameric heterocubane 4 in the triclinic space group P.The lattice constants of 4 (at 120 K) are: a = 1127.7(2), b = 1179.5(2), c = 2055.9(4) pm; α = 87.06(2), β = 87.83(2), γ = 75.37(2) deg. 4 contains a slightly distorted central Na4O4 cube with C8H14B and THF substituents at the oxygen and the sodium atoms respectively. 3 can also be prepared by heating an equimolar mixture of Na (5) and Na (6), or from (9H-9-BBN)2 and NaOH and from 9-HO-9-BBN and NaH in THF. - Keywords: 9-Sodiooxy-9-BBN, Cubane-Type (NaO)4, Crystal Structure, 9-BBN Substituents, THF-Borane Adduct
Koester, Roland,Seidel, G.,Blaeser, Dieter,Boese, Roland
p. 370 - 376
(2007/10/02)

Organosubstituted cis-1,2-Diborylalkenes as Electrophilic Chelates
Triethylborane (1), 9-ethyl-9-borabicyclononane (9-ethyl-9-BBN) (2), and the cis-1,2-diborylalkenes (Z)-R2BC(R')=C(Et)BEt2 react with alkali metal salts MX in toluene to give the borates MX-1, MX-2, and the cyclic cis-1,2-diborates , resp., with BHB- and B(OR)B-bridges (IR, Multi NMR).Reaction of 1, 2, and 3 - 6 with KCN leads to the monoborates KCN-1, KCN-2, and to the acyclic cis-1,2-diborates KCN-3 to KCN-7. - The cis-2-Boryl-1-silylalkenes (E)-Me3SiC(R')=C(Et)BEt2 and KX form the acyclic borates K.The cyclic salts KOtBu-4 and KOSiEt3-4 undergo a B-substituent exchange to the acyclic cis-1,2-diborates K (K-10: R = tBu; K-11: R = OSiEt3).Key Words: cis-1,2-Diborylalkenes, electron acceptors, anion sponge / Diborates, hexaorgano, μ-hydro, μ-alkoxy, alkali metal salts / Borates, hydrotriorgano- / Substituent exchange, diborates
Koester, Roland,Seidel, Guenter,Wagner, Klaus,Wrackmeyer, Bernd
p. 305 - 318
(2007/10/02)

Dithiocarboxylic Acids and Derivatives from Carboxylic Esters and Lactones with the Organoboron Sulfide Reagent (9-BBN)2S
Bis(1,5-cyclooctanediylboryl) sulfide (1) reacts with carboxylic esters to give the dithiocarboxylic 1,5-cyclooctanediylboryl esters 2a-f in high yields (2a: X-ray crystal structure analysis).Methanolysis of 2a-f leads to the dithiocarboxylic acids 5a-f, which form the corresponding piperidinium salts in the presence of piperidine.When cyclic esters (γ-, δ-lactones) are allowed to react with 1, the boryloxy-substituted dithiocarboxylic 1,5-cyclooctanediylboryl esters 3a-c are obtained.Key Words: (9-BBN)2S, reagent / OC-Sulfoborations / 1,2-Eliminations, of R2BOR', (R2B)2O / Dithiocarboxylic 1,5-cyclooctanediylboryl esters / Dithiocarboxylic acids
Koester, Roland,Kucznierz, Ralf,Seidel, Guenter,Betz, Peter
p. 1023 - 1032
(2007/10/02)

1,5-Cyclooctanediylboryl Selenides - Preparation, Characterisation, and Application
Bis(1,5-cyclooctanediylboryl) selenide (C8H14B)2Se (1) is obtained quantitatively from bis(9-borabicyclononane) (9-BBN)2 and elemental selenium in mesitylene at 150 deg C accompanied by evolution of hydrogen.Bis(1,5-cyclooctanediylboryl) diselenide (C8H14BSe)2 (2) is prepared efficiently from 1 with selenium in mesitylene at 120 deg C. 9-(Hydroseleno)-9-BBN (1H) together with 9-(phenylamino)-9-BBN (3) is easily obtained from 1 and aniline. - γ-Picoline (γPic) reacts with 1 to give the 2:1 addition compound γPic2-1, trimethylphosphane (TMP) with 1 forms the 1:1 addition compound TMP-1.Selenide 1 reacts spontaneously at room temperature with trialkoxyboranes B(OR)3 or with ClnAl(C2H5)3-n compounds exchanging the substituents. - The 1:1 addition compounds γPic-1H, TMP-1H, and Q-1H, are prepared from 1H with γPic, TMP, and quinuclidin (Q), respectively. - 1, 1H, and 2 undergo Se/O exchange reactions with organic and other oxygenated compounds and add to certain CC triple bonds.Pure Fe2Se3 is prepared quantitatively from 1 and Fe2O3. - Key Words: Boryl selenides, 1,5-cyclooctanediyl- / 9-Borabicyclononane, 9-hydroseleno- / Selenidation reagents / Lewis base - organoboron selenium compounds / Borane exchange reactions
Koester, Roland,Seidel, Guenter,Yalpani, Mohamed
p. 1815 - 1824
(2007/10/02)

Reactions of (Organo)phosphorus-Oxygen Compounds with Diorgano-hydro-boranes
Trialkyl phosphites P(OR)3 react with tetraalkyldiboranes(6) (R'2-BH)2 in a temperature-dependent manner between 20 and 130 deg C to form the trialkyl phosphite-boranes (RO)3P-BHR'2, (RO)3P-BH2R', and (RO)3P-BH3, which have various stabilities toward alcohols.With bis(9-borabicyclononane) (1c)2 the easily protolyzed addition compounds are obtained . - Diorgano phosphites (RO)2P(O)H , triorgano phosphates (RO)3PO , and the monosaccharide-diphenyl phosphates 4f, 4g, and 4h are reduced by (1a)2 or (1c)2 to give H2, PH3, and insoluble yellow phosphorus compounds, respectively.Phosphoric acid (4e), their derivatives OP(OBR2)3 , and phenylphosphonic acid C6H5P(O)(OH)2 (6) are not deoxygenated at 130 deg C by (1a)2 to (1c)2. - Diorganophosphoiic acids R2P(O)OH and phenylphosphinic acid C6H5(H)P(O)OH (5c) are reduced by (1a)2-(1c)2.Reaction of 5a with (1a)2 leads to the compounds B(C2H5)2 (8a-BH3), 2BC2H5 , and 3B . 5a reacts with (1c)2 under simultaneous formation of (C6H5)2PH (7) or (C6H5)PH-HBC8H14 (7-1c) and (C6H5)2POBC8H14 (8c) or (C6H5)2P(OBC8H14)-HBC8H14 (8c-1c). - 6 reacts with tetraethyldiboroxane (11a) to form a mixture of the oligomeric compounds - n - (6'a)n.
Koester, Roland,Schuessler, Wilhelm,Synoradzki, Ludwik
p. 1105 - 1116
(2007/10/02)

Zinc-promoted reductive coupling reactions. Reaction of sodium methoxyalkenyldialkylborates(1-) with alkenylzinc chlorides or zinc chloride
Sodium methoxyalkenyldialkylborates(1-) react with alkenylzinc chlorides or zinc chloride to provide excellent yields of symmetrical 1,3-dienes in an unprecedented reductive coupling process.
Molander, Gary A.,Zinke, Paul W.
p. 2161 - 2162
(2008/10/08)

Conjugate Addition-Elimination in the Reaction of B-1-Alkenyl-9-borabicyclononanes with 4-Methoxy-3-buten-2-one. A Convenient New Route to Conjugated Dienones
B1-Alkenyl-9-borabicyclononanes (B-1-alkenyl-9-BBN), easily and quantitatively prepared by the reaction of 9-BBN with various alkynes, undergo a facile reaction with the commercially available 4-methoxy-3-buten-2-one in diethyl ether at room temperature to provide conjugated dienones in essentially quantitative yields.
Molander, Gary A.,Singaram, Bakthan,Brown, Herbert C.
p. 5024 - 5025
(2007/10/02)

Boron Compounds, LIV. 17O NMR Studies of Cyclic Organo-Boron-Oxygen Compounds
17O-Chemical shifts (?17O) of various cyclic organo-boron-oxygen compounds (borolanes, borinanes, 9-borabicyclononanes, boroxins) are reported (Table 1).The ?17O values show that the magnetic screening of oxygen depends upon BO(pp)?-bonds.The contribution of the paramagnetic term ?(p) to the screening (?) of oxygen is evident from the comparison of ?17O of linear and bent systems, as is true for ?14N values of comparable compounds.Differences between 2-ethyl-1,3,2-dioxaborolanes and 2-ethyl-1,3,2-dioxaborinanes are shown by comparison of the ?17O data of the methyl substituted derivatives.
Wrackmeyer, Bernd,Koester, Roland
p. 2022 - 2034
(2007/10/02)