pKalculator: A pK_a predictor for C–H bonds

• Rasmus M. Borup,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2024, 20, 1614–1622, doi:10.3762/bjoc.20.144

• classifier as Ree et al. [14] have shown the opposite to be true for electrophilic aromatic substitutions. However, our regression model serves a dual function, that is, it accurately predicts pKa values and identifies the reaction site. Prediction of aryl C–H borylation sites In the previous section, we

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• 105. Prior to Rigotti and Bach, a select few 1,4-BCHs had been synthesised by Qin and co-workers [41] and Blanchard [56]. Alternatively, Hartwig and co-workers developed a C–H borylation reaction to access bridgehead-borylated 1,4-BCHs from monosubstituted BCHs [57]. The synthesis of polysubstituted

• could also be oxidised to acid 112, from which redox active ester 118 could be accessed. An alternative approach to 2-oxa-1,4-BCHs involves the C–H-borylation of monosubstituted 2-oxa-BCHs developed by Hartwig and co-workers (Scheme 12C) [57]. Functional groups including halides (in 120b), alcohols (in

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

Group 13 exchange and transborylation in catalysis

• Dominic R. Willcox and
• Stephen P. Thomas

Beilstein J. Org. Chem. 2023, 19, 325–348, doi:10.3762/bjoc.19.28

• experimentally determined free energy barrier of 28 kcal mol−1 for the second transborylation reaction (Scheme 3b) [60]. The seminal work from Fontaine reported that [1-(N-2,2,6,6-tetramethylpiperidinyl)-2-BH2-C6H4]2 catalysed the C–H borylation of heterocycles with HBpin [61], the first example of a catalytic

• an ambiphilic aluminium precatalyst, (Me2N)C6H4AlMe2, Thomas et al. were able to shut down hydroalumination by the alane and catalyse the C–H borylation of terminal alkynes with HBpin (Scheme 21) [96]. Through kinetic analysis, it was found that the rate of the alkynyl-Bpin product formation was

• was reported). Group 13 exchange. Borane-catalysed hydroboration of alkynes and the proposed mechanism. a) Borane-catalysed hydroboration of alkenes and the proposed mechanism. b) H-B-9-BBN-catalysed double hydroboration of alkynes and the proposed mechanism. a) Amine-borane-catalysed C‒H borylation

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• merging C–H activation and photocatalysis while using a single metal catalyst. In this case, an original Rh–NHC complex was used for the ortho-directed C–H borylation of phenylpyridine substrates (Figure 40) [102]. As previously, the irradiation with visible light allowed performing this challenging

Direct borylation of terrylene and quaterrylene

• Haruka Kano,
• Keiji Uehara,
• Kyohei Matsuo,
• Hironobu Hayashi,
• Hiroko Yamada and
• Naoki Aratani

Beilstein J. Org. Chem. 2020, 16, 621–627, doi:10.3762/bjoc.16.58

• )-catalyzed direct C–H borylation [22][23][24][25] gives 2,5,8,11-tetraborylated perylene [26]. The regioselectivity of the perylene borylation is determined by the steric factors rather than by the electron distribution in the arene and this regioselectivity complements that of electrophilic substitutions

Six-fold C–H borylation of hexa-peri-hexabenzocoronene

• Mai Nagase,
• Kenta Kato,
• Akiko Yagi,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2020, 16, 391–397, doi:10.3762/bjoc.16.37

• -catalyzed six-fold C–H borylation of HBC was successfully achieved by screening solvents. The crystal structure of hexaborylated HBC was confirmed via X-ray crystallography. Optoelectronic properties of the thus-obtained hexaborylated HBC were analyzed with the support of density functional theory

• calculations. The spectra revealed a bathochromic shift of absorption bands compared with unsubstituted HBC under the effect of the σ-donation of boryl groups. Keywords: C–H borylation; hexa-peri-hexabenzocoronene; iridium catalyst; X-ray crystallography; Introduction Polycyclic aromatic hydrocarbons (PAHs

• functional groups [15], hexaborylated HBC is expected to be a platform for the synthesis of diverse functionalized HBCs. Herein, we report the six-fold C–H borylation of unfunctionalized HBC (Figure 1c). By screening solvents, we have established suitable reaction conditions for the synthesis of

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

• Vânia F. Pais,
• Tristan Neumann,
• Ignacio Vayá,
• M. Consuelo Jiménez,
• Abel Ros and
• Uwe Pischel

Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254

• borylated, the choice of a suitable pyridine-hydrazone ligand [42] allowed to perform the borylation reactions at 55 °C, showing complete regioselectivity in the C–H borylation. This procedure afforded the dyes 16–19 in good to very good yields of 51–83% (Scheme 3). The introduction of the Bpin moiety

Iridium/N-heterocyclic carbene-catalyzed C–H borylation of arenes by diisopropylaminoborane

• Mamoru Tobisu,
• Takuya Igarashi and
• Naoto Chatani

Beilstein J. Org. Chem. 2016, 12, 654–661, doi:10.3762/bjoc.12.65

• C–H borylation of arenes has been widely used in organic synthesis because it allows the introduction of a versatile boron functionality directly onto simple, unfunctionalized arenes. We report herein the use of diisopropylaminoborane as a boron source in C–H borylation of arenes. An iridium(I

• borylation; iridium; N-heterocyclic carbene; Introduction Catalytic C–H borylation of arenes has become an essential tool in organic synthesis [1]. The eminent features of this methodology include 1) no directing group is needed, allowing the direct functionalization of simple arenes; 2) the

• served as the state-of-the-art catalyst for C–H borylation of arenes [2]. In addition to the Ir/dtbpy system, various other catalytic systems have also been developed. For example, base metals such as Fe [3][4][5][6], Co [7] and Ni [8][9] have been shown to be viable metal centers for the use as C–H

Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

• Tsuyuka Sugiishi,
• Hideki Amii,
• Kohsuke Aikawa and
• Koichi Mikami

Beilstein J. Org. Chem. 2015, 11, 2661–2670, doi:10.3762/bjoc.11.286

• . and Buchwald et al. used the Ruppert–Prakash reagent (CF3–SiMe3) directly as a CF3− source [46][47]. From CF3–SiMe3, Hartwig et al. developed a new combination of Ir-catalyzed C–H borylation and oxidative cross-coupling using [(phen)CF3Cu] [48]. Grushin et al. utilized fluoroform for the preparation

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• C–H borylation of several 1-substituted-3-(pentafluorosulfanyl)benzenes and applied the products of borylation to the Pd-catalyzed Suzuki–Miyaura reaction with aryl bromides or iodides. However, the reaction is limited to borylations in position five of 1-substituted-3-(pentafluorosulfanyl)benzenes

Metal–ligand multiple bonds as frustrated Lewis pairs for C–H functionalization

• Matthew T. Whited

Beilstein J. Org. Chem. 2012, 8, 1554–1563, doi:10.3762/bjoc.8.177

• Ir(I) center followed by hydride migration [64][79][80]. The well-developed C–H borylation chemistry of Hartwig and others provides an indication that cooperation may be operative to some extent in the activation of C–H bonds at metal boryls [81][82][83][84], though the exact mechanism of C–H