- Merging Halogen-Atom Transfer (XAT) and Copper Catalysis for the Modular Suzuki-Miyaura-Type Cross-Coupling of Alkyl Iodides and Organoborons
-
We report here a mechanistically distinct approach to achieve Suzuki-Miyaura-type cross-couplings between alkyl iodides and aryl organoborons. This process requires a copper catalyst but, in contrast with previous approaches based on palladium and nickel
- Zhang, Zhenhua,Górski, Bartosz,Leonori, Daniele
-
supporting information
p. 1986 - 1992
(2022/02/01)
-
- Manganese(III)-Promoted Double Carbonylation of Anilines Toward α-Ketoamides Synthesis
-
Employing anilines as nucleophiles in double carbonylation is a longstanding challenge. In this communication, a Mn(III)-promoted double carbonylation of alkylborates or Hantzsch esters with anilines toward the synthesis of α-ketoamides has been developed. By using easily available potassium alkyltrifluoroborates or Hantzsch esters as the starting material, and cheap and non-toxic Mn(OAc)3 ? 2H2O as the promotor, a broad range of alkyl α-ketoamide derivatives were synthesized in moderate to good yields with excellent selectivity. (Figure presented.).
- Chen, Bo,Kuai, Chang-Sheng,Xu, Jian-Xing,Wu, Xiao-Feng
-
supporting information
p. 487 - 492
(2021/12/06)
-
- Light-Mediated Sulfur-Boron Exchange
-
Interaction of sulfides bearing a tetrafluoropyridinyl group with bis(catecholato)diboron followed by treatment with pinacol and triethylamine affording pinacol boronic esters is described. The reaction is promoted by an organic photocatalyst (3DPA2FBN) u
- Panferova, Liubov I.,Dilman, Alexander D.
-
supporting information
p. 3919 - 3922
(2021/05/29)
-
- Visible-light-driven graphene supported Cu/Pd alloy nanoparticle-catalyzed borylation of alkyl bromides and chlorides in air
-
A highly efficient photocatalytic protocol for borylation of alkyl bromides and chlorides with graphene supported Cu/Pd alloy nanoparticles as a heterogeneous catalyst is reported. This photocatalytic system operates with visible light in air, providing a wide range of primary and secondary alkyl halides with B2pin2 or B2neop2 in high yields at low temperatures, thereby demonstrating its broad utility and functional group tolerance. The high performance is attributed to a synergistic effect of localized surface plasmon resonance (LSPR) of Cu and charge transfer from Cu to Pd due to the alloy surface charge heterogeneity. Transfer of energetic electrons from Pd to electrophilic alkyl halides lead to the formation of the alkyl radicals, which quickly react with a nucleophilic adduct of a diboron compound with base adsorbed on the positively charged Cu sites to form the corresponding borylation product.
- Jiao, Zhi-Feng,Tian, Ya-Ming,Guo, Xiao-Ning,Radius, Udo,Braunschweig, Holger,Marder, Todd B.,Guo, Xiang-Yun
-
p. 258 - 265
(2021/02/16)
-
- N-Methylation and Trideuteromethylation of Amines via Magnesium-Catalyzed Reduction of Cyclic and Linear Carbamates
-
A new reduction of carbamates to N-methyl amines is presented. The magnesium-catalyzed reduction reaction allows the conversion of cyclic and linear carbamates, including N-Boc protected amines, into the corresponding N-methyl amines and amino alcohols which are of significant interest due to their presence in many biologically active molecules. Furthermore, the reduction can be extended to the formation of N-trideuteromethyl labeled amines.
- Magre, Marc,Szewczyk, Marcin,Rueping, Magnus
-
supporting information
p. 3209 - 3214
(2020/04/10)
-
- Efficient synthesis of alkylboronic esters: Via magnetically recoverable copper nanoparticle-catalyzed borylation of alkyl chlorides and bromides
-
We report a magnetically separable Cu nanocatalyst (Fe-DOPA-Cu) for the borylation of alkyl halides with alkoxy diboron reagents, providing alkylboronic esters in high yields, with broad functional group tolerance under mild reaction conditions. The procedure is also applicable to the borylation of benzyl chlorides and bromides. Radical clock experiments support a radical-mediated process. Easy recycling of the catalyst resulted in no significant loss of activity up to ten runs.
- Shegavi, Mahadev L.,Agarwal, Abhishek,Bose, Shubhankar Kumar
-
supporting information
p. 2799 - 2803
(2020/06/17)
-
- Magnesium-Catalyzed Hydroboration of Terminal and Internal Alkynes
-
A magnesium-catalyzed hydroboration of alkynes providing good yields and selectivities for a wide range of terminal and symmetrical and unsymmetrical internal alkynes has been developed. The compatibility with many functional groups makes this magnesium c
- Magre, Marc,Maity, Bholanath,Falconnet, Alban,Cavallo, Luigi,Rueping, Magnus
-
supporting information
p. 7025 - 7029
(2019/04/26)
-
- Chemoselective Luche-Type Reduction of α,β-Unsaturated Ketones by Magnesium Catalysis
-
The chemoselective reduction of α,β-unsaturated ketones by use of an economic and readily available Mg catalyst has been developed. Excellent yields for a wide range of ketones have been achieved under mild reaction conditions, short times, and low catalyst loadings (0.2-0.5 mol %).
- Jang, Yoon Kyung,Magre, Marc,Rueping, Magnus
-
supporting information
p. 8349 - 8352
(2019/10/16)
-
- Pd-Catalyzed Conjunctive Cross-Coupling between Grignard-Derived Boron “Ate” Complexes and C(sp2) Halides or Triflates: NaOTf as a Grignard Activator and Halide Scavenger
-
Catalytic enantioselective conjunctive cross-couplings that employ Grignard reagents are shown to furnish an array of nonracemic chiral organoboronic esters in an efficient and highly selective fashion. The utility of sodium triflate in facilitating this reaction is two-fold: it enables “ate” complex formation and overcomes catalytic inhibition by halide ions.
- Lovinger, Gabriel J.,Aparece, Mark D.,Morken, James P.
-
supporting information
p. 3153 - 3160
(2017/03/11)
-
- A boron reagent dimethylamine base boric acidfrequency ester, synthesis and use
-
The invention relates to novel boronizing agent dimethylamino boronic acid pinacol ester PinB(DMA) the structure of which is in the specification. The specific synthesis steps are as follows: reacting raw material B(NME2)3 with pinacol for 2-5 hours under the solvent-free condition at the temperature of 50-70 DEG C; and distilling under the vacuum condition of minus 0.1 Mpa, and collecting fraction of 45-50 DEG C, namely the fraction is the product. The PinB(DMA) provided by the invention has the characteristics that water sensitivity is low, structure is stable, ultralow temperature reaction can be avoided when the PinB(DMA) participates in boronization reaction, and the like; and the market value of the PinB(DMA) is important. Compared with the similar processes, the synthesis process of the boronizing agent in the invention has the obvious characteristics of simple reaction steps, mild process condition, no solvent reaction, good process stability and simple post-treatment; and the boronizing agent prepared by the synthesis process is high in yield and good in purity. The boronizing agent is good in purity and has wide application prospect in the boronization reaction.
- -
-
Paragraph 0027-0028
(2016/10/08)
-
- Selective and Serial Suzuki-Miyaura Reactions of Polychlorinated Aromatics with Alkyl Pinacol Boronic Esters
-
Among cross-coupling reactions, the Suzuki-Miyaura transformation stands out because of its practical advantages, including the commercial availability and low toxicity of the required reagents, mild reaction conditions, and functional group compatibility. Nevertheless, few conditions can be used to cross-couple alkyl boronic acids or esters with aryl halides, especially 2-pyridyl halides. Herein, we describe two novel Suzuki-Miyaura protocols that enable selective conversion of polychlorinated aromatics, with a focus on reactions to convert 2,6-dichloropyridines to 2-chloro-6-alkylpyridines or 2-aryl-6-alkylpyridines.
- Laulhé, Sébastien,Blackburn, J. Miles,Roizen, Jennifer L.
-
supporting information
p. 4440 - 4443
(2016/09/09)
-
- Amino acid-promoted C-H alkylation with alkylboronic acids using a removable directing group
-
Palladium-catalyzed C-H alkylation reaction with alkylboronic acids has successfully been developed using a removable pyridyldiisopropylsilyl directing group. The amino acid played a crucial role as a ligand in the reaction. The alkylation protocol is also applicable to the coupling of C(sp3)-H bonds with alkylboronic acids.
- Zhang, Yanghui,Zhang, Yu,Jiang, Hang,Chen, Dushen
-
supporting information
p. 4585 - 4589
(2016/06/09)
-
- Magnesium-catalysed nitrile hydroboration
-
A β-diketiminato n-butylmagnesium complex is presented as a selective precatalyst for the reductive hydroboration of organic nitriles with pinacolborane (HBpin). Stoichiometric reactivity studies indicate that catalytic turnover ensues through the generat
- Weetman, Catherine,Anker, Mathew D.,Arrowsmith, Merle,Hill, Michael S.,Kociok-K?hn, Gabriele,Liptrot, David J.,Mahon, Mary F.
-
p. 628 - 641
(2015/12/30)
-
- Borylation of primary and secondary alkyl bromides catalyzed by Cu2O nanoparticles
-
A Cu2O nanoparticle catalyzed borylation of activated and unactivated alkyl bromides is developed, using bis(pinacolato)diboron as a boron source. To the best of our knowledge this is the first report of a heterogeneous Cu2O nanocata
- Zhou, Xin-Feng,Wu, Ya-Dong,Dai, Jian-Jun,Li, Yong-Jia,Huang, Yu,Xu, Hua-Jian
-
p. 46672 - 46676
(2015/06/16)
-
- Iron-catalyzed borylation of alkyl, allyl, and aryl halides: Isolation of an iron(I) boryl complex
-
Activation of B2pin2 with tBuLi facilitates the Fe-catalyzed borylation of alkyl, allyl, benzyl, and aryl halides via the formation of Li[B2pin2(tBu)] (1). The reaction of 1 with a representative iron phosphine precatalyst generates the unique iron(I) boryl complex [Fe(Bpin)(dpbz)2] (2).
- Bedford, Robin B.,Brenner, Peter B.,Carter, Emma,Gallagher, Timothy,Murphy, Damien M.,Pye, Dominic R.
-
p. 5940 - 5943
(2015/01/08)
-
- Magnesium catalysis of imine hydroboration
-
The β-diketiminato magnesium alkyl complex [LMgnBu] (L=CH{CMe(NDipp)}2, Dipp=diisopropylphenyl) is shown to be a highly effective precatalyst for the hydroboration of alkyl and aryl substituted aldimines and ketimines with pinacol borane (HBpin). Catalysis is proposed to occur through a sequence of Mg-N/B-H metathesis and rate-determining Mg-H/N=C insertion steps, a proposal strongly supported by stoichiometric studies and kinetic analysis. The reactions are observed to proceed through the intermediacy of well-defined magnesium amides, two examples of which have been isolated and structurally characterized. Mechanistic investigations suggest that the catalytic rate-determining process occurs at an isolated magnesium center and requires the presence of two molecules of the imine substrate for effective turnover. This latter observation is rationalized as a requirement for the secondary substrate molecule to displace HBpin from the coordination sphere of the catalytic magnesium center.
- Arrowsmith, Merle,Hill, Michael S.,Kociok-Koehn, Gabriele
-
supporting information
p. 2776 - 2783
(2013/03/14)
-
- Suzuki-Miyaura cross-couplings of secondary allylic boronic esters
-
Palladium-catalyzed cross-coupling reactions of secondary allylic boronic esters with iodoarenes were demonstrated under the conditions previously described for the coupling of benzylic substrates. The regioselectivity of the process was largely dictated by the pattern of olefin substitution. The Royal Society of Chemistry 2012.
- Glasspoole, Ben W.,Ghozati, Kazem,Moir, Jonathon W.,Crudden, Cathleen M.
-
supporting information; experimental part
p. 1230 - 1232
(2012/02/15)
-
- Preparative synthesis via continuous flow of 4,4,5,5-tetramethyl-2-(3- trimethylsilyl-2-propynyl)-1,3,2-dioxaborolane: A general propargylation reagent
-
A scalable process for the preparation of 4,4,5,5-tetramethyl-2-(3- trimethylsilyl-2-propynyl)-1,3,2-dioxaborolane from trimethylsilylpropyne, isopropyl pinacol borate, and n-butyllithium is described. Problems associated with implementing a typical aqueous workup and batch process into production due to borolane ate equilibration and protonolysis are presented. To address these issues, a continuous-flow and distillation process was developed which efficiently produced 297 kg of the key propargylation reagent.
- Fandrick, Daniel R.,Roschangar, Frank,Kim, Chunyoung,Hahm, Byoung J.,Cha, Myoung H.,Kim, Hyoun Y.,Yoo, Gyesang,Kim, Taeyun,Reeves, Jonathan T.,Song, Jinhua J.,Tan, Zhulin,Qu, Bo,Haddad, Nizar,Shen, Sherry,Grinberg, Nelu,Lee, Heewon,Yee, Nathan,Senanayake, Chris H.
-
supporting information; scheme or table
p. 1131 - 1140
(2012/08/13)
-
- Magnesium-catalysed hydroboration of aldehydes and ketones
-
The heteroleptic magnesium alkyl complex [CH{C(Me)NAr}2Mg nBu] (Ar = 2,6-iPr2C6H3) is reported as a highly efficient pre-catalyst for the hydroboration of aldehydes and ketones with pinacolborane. The Royal Society of Chemistry 2012.
- Arrowsmith, Merle,Hadlington, Terrance J.,Hill, Michael S.,Kociok-Koehn, Gabriele
-
supporting information; experimental part
p. 4567 - 4569
(2012/06/05)
-
- Copper(I)-catalyzed boryl substitution of unactivated alkyl halides
-
Borylation of alkyl halides with diboron proceeded in the presence of a copper(I)/Xantphos catalyst and a stoichiometric amount of K(O-t-Bu) base. The boryl substitution proceeded with normal and secondary alkyl chlorides, bromides, and iodides, but alkyl sulfonates did not react. Menthyl halides afforded the corresponding borylation product with excellent diastereoselectivity, whereas (R)-2-bromo-5-phenylpentane gave a racemic product. Reaction with cyclopropylmethyl bromide resulted in ring-opening products, suggesting the reaction involves a radical pathway.
- Ito, Hajime,Kubota, Koji
-
supporting information; experimental part
p. 890 - 893
(2012/05/05)
-
- Magnesium-catalyzed hydroboration of pyridines
-
Reaction of catalytic quantities of a β -diketiminato n-butylmagnesium complex with pinacol-borane in the presence of pyridine derivatives provides facile access to borylated dihydropyridines. The reaction is applicable to a wide range of monocyclic and fused-ring pyridine derivatives and catalytic turnover is proposed to occur through a well-defined sequence of Mg-H/pyridine dearomatization and Mg-N/B-H sigma bond metathesis steps.
- Arrowsmith, Merle,Hill, Michael S.,Hadlington, Terrance,Kociok-Koehn, Gabriele,Weetman, Catherine
-
scheme or table
p. 5556 - 5559
(2012/01/04)
-
- Iridium-catalyzed hydroboration of alkenes with pinacolborane
-
Hydroboration of terminal and internal alkenes with pinacolborane (1.2 equiv) was carried out at room temperature in the presence of an iridium(I) catalyst (3 mol%). Addition of dppm (2 equiv) to [Ir(cod)Cl]2 gave the best catalyst for hydroboration of aliphatic terminal and internal alkenes at room temperature, resulting in addition of the boron atom to the terminal carbon of 1-alkenes with more than 99% selectivities. On the other hand, a complex prepared from dppe (2 equiv) and [Ir(cod)Cl]2 resulted in the best yields for vinylarenes such as styrene. These complexes exhibited higher levels of catalyst activity and selectivity than those of corresponding rhodium complexes. Graphical Abstract.
- Yamamoto, Yasunori,Fujikawa, Rhyou,Umemoto, Tomokazu,Miyaura, Norio
-
p. 10695 - 10700
(2007/10/03)
-
- P1 Phenethyl peptide boronic acid inhibitors of HCV NS3 protease
-
A series of peptide boronic acids containing extended, hydrophobic P1 residues was prepared to probe the shallow, hydrophobic S1 region of HCV NS3 protease. The p-trifluoromethylphenethyl P1 substituent was identified as optimal with respect to inhibitor potency for NS3 and selectivity against elastase and chymotrypsin.
- Priestley,De Lucca, Indawati,Ghavimi, Bahman,Erickson-Viitanen, Susan,Decicco, Carl P.
-
p. 3199 - 3202
(2007/10/03)
-
- The influence of boryl substituents on the formation and reactivity of adjacent and vicinal free radical centers
-
Radicals containing α-boronate substituents were generated by bromine abstraction from 1-bromo-alkyldioxaborolanes (boronic esters), by addition to vinyl boronate, and by hydrogen abstraction from alkyldioxaborolanes and observed by EPR spectroscopy. Unsymmetrically substituted α-boronate radicals displayed selective line broadening in their low-temperature spectra from which barriers to internal rotation about ?CH2-B(OR′)OR bonds were found to be 3 ± 1 kcal mol-1. Use of an empirical relationship between barrier height and bond dissociation energy led to BDE[(RO)2BCH2-H] = 98.6 kcal mol-1. Rate constants for hydrogen abstraction from 2,4,4,5,5-pentamethyl-1,3,2-dioxaborolane by tert-butoxyl radicals were determined from competitive EPR and product studies and found to be relatively small, comparable to those of unactivated methyl groups. Hydrogen abstraction from bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-methane was found to be extremely difficult. The structures and energetics of α-boronate radicals were computed by DFT methods (B3LYP/6-31G*). This predicted reductions in the rotation barriers of X2B-CH2? radicals for increasing alkoxy substitution at B (X = Me or MeO) and corresponding increases in the X2BCH2-H bond dissociation energies. The B3LYP-computed BDE[(MeO)2BCH2-H] was in excellent agreement with the analogous value derived from the experimental rotation barrier. Radicals containing β-boronate substituents were generated from the corresponding 2-bromoalkylboronic esters and characterized by EPR spectroscopy. At higher temperatures the main product from trialkyltin and triethylsilyl radical promoted reactions of 2-(2-bromohexyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was 1-hexene. This was best accounted for by a mechanism involving initial SH2 attack on the borolane and subsequent bromine atom elimination from the displaced 2-bromohexyl radical.
- Walton, John C.,McCarroll, Andrew J.,Chen, Qiao,Carboni, Bertrand,Nziengui, Roger
-
p. 5455 - 5463
(2007/10/03)
-