1065498-70-5Relevant articles and documents
CuII-catalyzed regioselective borylation of alkynes and alkenes
Liu, Shiwen,Zeng, Xiaojun,Xu, Bo
, p. 3706 - 3710 (2016)
We developed a regioselective borylation of alkynes and alkenes protocol based on air-stable CuII/multi-dentate ligand system. Our catalytic system gives exclusive β-borylation products for most substrates in excellent chemical yields. We propo
4-Cyanopyridine-catalyzed anti-Markovnikov selective hydroboration of alkenes
Xu, Rui,Lu, Guo-Ping,Cai, Chun
, p. 16456 - 16459 (2018)
A highly selective anti-Markovnikov hydroboration reaction of alkenes with bis(pinacolato)diboron catalyzed by 4-cyanopyridine has been described. This strategy provides an efficient, practical and environmentally benign protocol for the construction of alkylboronates in moderate to good yields under metal-free conditions. A radical mechanism proceeding via a 4-cyanopyridine-ligated boryl radical was proposed.
Hydroboration of terminal olefins with pinacolborane catalyzed by new 2-iminopyrrolyl iron(ii) complexes
Cruz, Tiago F. C.,Pereira, Laura C. J.,Waerenborgh, Jo?o C.,Veiros, Luís F.,Gomes, Pedro T.
, p. 3347 - 3360 (2019)
Four paramagnetic 14-electron tetracoordinated Fe(ii) complexes of 5-substituted-2-iminopyrrolyl ligands of the type [Fe{κ2N,N′-5-R-NC4H2-2-C(H)N(2,6-iPr2-C6H3)}(Py)Cl], with R = 2,6-Me2-C6H3 (1a), 2,4,6-iPr3-C6H2 (1b), 2,4,6-Ph3-C6H3 (1c) and CPh3 (1d), were synthesized in moderate yields by reacting the respective 5-substituted-2-iminopyrrolyl potassium salts KLa-d with FeCl2(Py)4 in toluene. Complexes 1a-d were characterized by 1H NMR, FTIR spectroscopies, elemental analysis and by the Evans method, the corresponding effective magnetic moments showing a high-spin electronic nature. X-ray diffraction studies on complexes 1a and 1c showed distorted tetrahedral coordination geometries. Complexes 1a-c, activated with K(HBEt3), were efficient catalyst systems for the hydroboration of several terminal alkenes with pinacolborane in good to high yields (50-90%). This system mainly yielded the respective anti-Markovnikov addition products, except when styrenes were used. A screening of the hydroboration of styrene catalyzed by complexes 1a-c activated with K(HBEt3) showed that the selectivity in the Markovnikov product increased with increasing steric bulkiness of the R group, exhibiting selectivities up to 91%. Additionally, the stoichiometric reaction of complex 1b with K(HBEt3) over 30 minutes yielded the mixture of hydride species 2 and 22 (mixture I). On the other hand, when reacting the same components over 16 h, the Fe(i) complex 3 was also identified in the mixture, in addition to 2 + 22 (mixture II). These mixtures were characterized in solution by the Evans method and in the solid state by elemental analysis, 57Fe M?ssbauer and FTIR spectroscopies, compounds 22 and 3 being also analyzed by X-ray diffraction. These results suggest that the corresponding catalytic cycle follows the borane oxidative addition route to a Fe(i) species.
Markovnikov-Selective Hydroboration of Vinylarenes Catalyzed by a Cobalt(II) Coordination Polymer
Zhang, Guoqi,Wu, Jing,Li, Sihan,Cass, Sean,Zheng, Shengping
, p. 7893 - 7897 (2018)
Highly efficient and practical hydroboration of alkenes has been catalyzed by an inexpensive and air-stable cobalt(II) coordination polymer (CP) in the presence of KOtBu. Complete conversion of alkenes to alkylboronates were performed within just 5 min with low catalyst loading (0.025 mol%), achieving the record high turnover frequencies of up to 47 520 h-1. For a range of vinylarenes, unusual Markovnikov selectivity was observed.
Hydroboration of Terminal Alkenes and trans-1,2-Diboration of Terminal Alkynes Catalyzed by a Manganese(I) Alkyl Complex
Kirchner, Karl,St?ger, Berthold,Veiros, Luis F.,Weber, Stefan,Zobernig, Daniel
, p. 24488 - 24492 (2021)
A MnI-catalyzed hydroboration of terminal alkenes and a 1,2-diboration of terminal alkynes with pinacolborane (HBPin) is described. For alkenes, anti-Markovnikov hydroboration takes place; for alkynes the reaction proceeds with excellent trans-1,2-selectivity. The most active pre-catalyst is bench-stable alkyl bisphosphine MnI complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn–alkyl bond to yield an acyl intermediate, which undergoes B?H bond cleavage of HBPin (for alkenes) and rapid C?H bond cleavage (for alkynes), forming the active MnI boryl and acetylide catalysts [Mn(dippe)(CO)2(BPin)] and [Mn(dippe)(CO)2(C≡CR)], respectively. A broad variety of aromatic and aliphatic alkenes and alkynes was efficiently and selectively borylated. Mechanistic insights are provided based on experimental data and DFT calculations revealing that an acceptorless reaction is operating involving dihydrogen release.
DMAP-accelerated rhodium(I) chloride catalyzed hydroboration of vinylarenes
Endo, Kohei,Hirokami, Munenao,Takeuchi, Kazunari,Shibata, Takanori
, p. 3231 - 3233 (2008)
Regioselective hydroboration of vinylarenes catalyzed by a Rh(I)-DPPB complex proceeded rapidly when DMAP was used as an additive. The catalyst loading could be reduced to 0.4 mol% Rh(I) to furnish the desired products in good to excellent yield with high
Boron Lewis Acid-Catalyzed Hydroboration of Alkenes with Pinacolborane: BArF3Does What B(C6F5)3Cannot Do!
Yin, Qin,Kemper, Sebastian,Klare, Hendrik F. T.,Oestreich, Martin
, p. 13840 - 13844 (2016)
The transition-metal-free hydroboration of various alkenes with pinacolborane (HBpin) initiated by tris[3,5-bis(trifluoromethyl)phenyl]borane (BArF3) is reported. The choice of the boron Lewis acid is crucial as the more prominent boron Lewis acid tris(pentafluorophenyl)borane (B(C6F5)3) is reluctant to react. Unlike B(C6F5)3, BArF3is found to engage in substituent redistribution with HBpin, resulting in the formation of ArFBpin and the electron-deficient diboranes [H2BArF]2and [(ArF)(H)B(μ-H)2BArF2]. These in situ-generated hydroboranes undergo regioselective hydroboration of styrene derivatives as well as aliphatic alkenes with cis diastereoselectivity. Another ligand metathesis of these adducts with HBpin subsequently affords the corresponding HBpin-derived anti-Markovnikov adducts. The reactive hydroboranes are regenerated in this step, thereby closing the catalytic cycle.
Electrochemically promoted decarboxylative borylation of alkyl N-hydroxyphthalimide esters
Dai, Jian-Jun,Fang, Wen,Teng, Xin-Xin,Xu, Hua-Jian,Xu, Jun
, (2021)
An electrochemically promoted decarboxylative borylation reaction is reported. The reaction proceeds under mild conditions in an undivided cell without use of transition metal- or photo-catalysts. The key feature of the reaction is the compatibility of di
Borohydrogenation reaction method of halide calcium catalyzed olefins
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Paragraph 0030-0035, (2022/01/12)
The present invention discloses a method of borohydrogenation of olefins catalyzed by calcium halide, comprising, under anhydrous and anaerobic conditions, calcium halide added to the mixture of olefins and pinacol borane, stirred at 90 to 110 ° C for 6 t
Site-Fixed Hydroboration of Terminal and Internal Alkenes using BX3/iPr2NEt**
Cui, Xin,Hu, Chenyang,Li, Sida,Liu, Liu Leo,Wu, Lipeng,Zhang, Jiong
, p. 26238 - 26245 (2021/11/09)
An unprecedented and general hydroboration of alkenes with BX3 (X=Br, Cl) as the boration reagent in the presence of iPr2NEt is reported. The addition of iPr2NEt not only suppresses alkene polymerizat
