Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• , wherein the activation of complex 74 takes place through SET under constant current electrolysis [64]. The Glorius and Y. Fu groups have independently proposed the formation of analogous charge-transfer complexes involving NHPI esters, bis(pinacolato)diboron (B2pin2), and Lewis bases (pyridine or

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• C38H28N, 498.2216; found, 498.2217; [M + H]+ calcd for C38H27BrN, 576.1321; found, 576.1331; [M + H]+ calcd for C38H26Br2N, 654.0427; found, 654.0438. The mixture of the above crude product (1.00 g), bis(pinacolato)diboron (881 mg, 3.47 mmol), KOAc (2.04 g, 20.81 mmol), and Pd(dppf)Cl2 (70.8 mg, 0.087

• -N-carbazole 2 in good yield (87%). Compound 2 was then converted to the boronic ester intermediate 3 in 41% yield over two steps: monobromination at the carbazole unit of 2 with NBS/THF at low temperature giving the unisolated mixed brominated product followed by borylation with bis(pinacolato

• )diboron catalyzed by Pd(dpf)Cl2/KOAc. Finally, TPECNz was obtained as red solid in a reasonable yield by a Suzuki-type cross-coupling reaction between 3 and 4,9-dibromonaphtho[2,3-c][1,2,5]thiadiazole. The chemical structure and purity of compound 3 were verified by 1H NMR, 13C NMR, and high-resolution

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• were accomplished by using 5 mol % of a chiral monodentate NHC–Cu complex derived from the readily available C1-symmetric imidazolium salt 115 and employing commercially available bis(pinacolato)diboron, B2(pin)2. The desired β-borylcarbonyls were obtained in 60–98% yield and >98:2 er. Following a

• of internal alkynes with bis(pinacolato)diboron to obtain vinylboranes. The reaction could be performed in air. Tsuji and co-workers [84] prepared 2-boryl-substituted 1,3-butadienes, which are otherwise difficult to synthesize, through NHC–CuCl-catalyzed borylation of α-alkoxyallenes with B2(pin)2

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• driving force (evolution of CO2). Triethylphosphite P(OEt)3 and bis(pinacolato)diboron B2pin2 were successfully applied as trapping reagents for redox-neutral photo-Arbuzov and borylation reactions with good to excellent yields (Figure 11D). Additionally, the authors were able to perform the net-reductive

• (pinacolato)diboron (B2pin2) as trapping agents for C(sp2)–Het(Arene) couplings (Figure 9B). The successful activation of electron-neutral and electron-rich aryl halides via conPET mostly remained an unsolved challenge until the Nicewicz group in 2020 disclosed a modified acridinium (Fukuzumi) salt Mes-Acr

• electrogeneration favor a preassembly with Ar−X that i) upon photoexcitation accesses excited states higher than the first (D1) to bolster reactivity and/or ii) following PET assists in the Ar−X•− fragmentation step. The scope was expanded using triethylphosphite (P(OEt)3), dimethyl disulfide (MeSSMe) and bis

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

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• intercepted by an electrophile to generate the difunctionalized system. This methodology has been applied several times to strained bicyclic alkenes with a variety of electrophiles. In 2015, Hirano and Miura developed a Cu-catalyzed aminoboration of bicyclic alkenes 1 with bis(pinacolato)diboron (B2pin2) (53

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• ), yield: 80.0%; (d) bis(pinacolato)diboron, KOAc, Pd(dppf)Cl2, toluene, N2, 110 °C, 16 h, yield: 11.9%.; (e) 1-bromo-4-iodobenzene, Pd(PPh3)4, K2CO3, TOL, EtOH, H2O, N2, reflux, 8 h, yield: 92.9%; (f

Palladium-catalyzed solid-state borylation of aryl halides using mechanochemistry

• Koji Kubota,
• Emiru Baba,
• Tamae Seo,
• Tatsuo Ishiyama and
• Hajime Ito

Beilstein J. Org. Chem. 2022, 18, 855–862, doi:10.3762/bjoc.18.86

• , Japan 10.3762/bjoc.18.86 Abstract This study describes the solid-state palladium-catalyzed cross-coupling between aryl halides and bis(pinacolato)diboron using ball milling. The reactions were completed within 10 min for most aryl halides to afford a variety of synthetically useful arylboronates in

• Discussion Initially, we conducted an optimization study on the mechanochemical cross-coupling between 2-bromo-6-methoxynaphthalene (1a, 0.3 mmol) and bis(pinacolato)diboron (2, 1.2 equiv) in the presence of Pd(OAc)2 (2 mol %), KOAc (3.0 equiv), and H2O (60 μL) as a liquid additive [43][44][45] (Table 1

Unexpected chiral vicinal tetrasubstituted diamines via borylcopper-mediated homocoupling of isatin imines

• Marco Manenti,
• Leonardo Lo Presti,
• Giorgio Molteni and
• Alessandra Silvani

Beilstein J. Org. Chem. 2022, 18, 303–308, doi:10.3762/bjoc.18.34

• diffraction analysis and proved to be single diastereoisomers and atropisomers. A plausible mechanism for the one-pot Cu(II)-catalyzed Bpin addition to the isatin-derived ketimine substrate and subsequent homocoupling is described. Keywords: atropoisomer; bis(pinacolato)diboron; 3,3′-bisoxindole; N-tert

• intramolecular transformation [14], the insertion of a boron atom into chiral oxindoles is scarcely reported. Continuing with such previous project, next we looked at the copper-mediated reaction of isatin-derived, optically pure sulfinyl ketimines with bis(pinacolato)diboron, as a potential way to access

• . Results and Discussion We began our investigation using the known (R)-1-methylisatin-derived N-tert-butanesulfinyl ketimine 1a, bis(pinacolato)diboron, CuSO4/(Cy)3P catalyst and benzylamine, as reported in Scheme 1. The first reaction was carried out at room temperature in toluene/water (5:1), as

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• [36] do not give the exact values of the molecular weight of the obtained polymers, they draw a conclusion about the influence of the molecular weight on the efficiency of the cells (Table 4). Thus, when using polymer 24b obtained by the Suzuki reaction with bis(pinacolato)diboron, the OSC efficiency

Total synthesis of decarboxyaltenusin

• Lucas Warmuth,
• Aaron Weiß,
• Marco Reinhardt,
• Anna Meschkov,
• Ute Schepers and
• Joachim Podlech

Beilstein J. Org. Chem. 2021, 17, 224–228, doi:10.3762/bjoc.17.22

• protection to the bis(benzyl ether) 5b using standard conditions (Scheme 2) [27]. The preparation of boronate 6b applying the conditions used for the silylated substrate 6a (vide supra) led to a mediocre 44% yield, but the utilization of a palladium-catalyzed borylation with bis(pinacolato)diboron afforded

• -1,3,2-dioxaborolane, THF, −78 °C, 0.45–2 h, rt, 18 h (57%); R = Bn: bis(pinacolato)diboron, Pd(dppf)Cl2·CH2Cl2 (cat.), KOAc, dioxane, 80 °C, 17 h (55%). Synthesis of aryl bromides 9. Conditions: f) BBr3, −78 °C to rt, 18 h (71%); g) R = TBS: TBSCl, DMAP, imidazole, DMF, 55 °C, 4 h (73%); R = Bn: BnBr

An overview on disulfide-catalyzed and -cocatalyzed photoreactions

• Yeersen Patehebieke

Beilstein J. Org. Chem. 2020, 16, 1418–1435, doi:10.3762/bjoc.16.118

• groups that contain heteroatoms. Ogawa and co-workers reported a class of efficient diboration reactions. Under light irradiation, disulfide was used as the photocatalyst to facilitate the addition of bis(pinacolato)diboron (B2pin2) to terminal alkynes [19], and the corresponding diboryl alkenes were

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• % aqueous NaOH in the presence of tetrabutylammonium iodide (TBAI) [33][34][35]. Upon chromatography 3-bromo-9-hexylcarbazole (4) was obtained as a liquid in good yield. 3-Bromo-9-hexylcarbazole (4) was then converted into the pinacol boronic ester by treating with bis(pinacolato)diboron in the presence of

• ), 0.86 (t, J = 7.0 Hz, 4H). (9-Hexylcarbazole-3-yl)boronic acid pinacol ester (5): 5 was synthesised as reported previously [36][37]. Bis(pinacolato)diboron (423 mg, 1.7 mmol), potassium acetate (446 mg, 4.5 mmol) and dichlorobis(triphenylphosphine)palladium(II) (35 mg, 0.05 mmol) catalyst were added to

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

• terrylene was isolated. Note that the terrylene is slightly soluble in halogenated solvents, hence a 1H NMR spectrum in CDCl3 at room temperature can be measured. The reaction of terrylene (0.16 mmol), bis(pinacolato)diboron (8 equiv), [Ir(OMe)cod]2 (10 mol %) and di-tert-butylbipyridyl (20 mol %) in 1,4

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

• and then refilled with nitrogen. To this vessel were added 3 (100 mg, 78.3 μmol, 1.0 equiv), Pd(dppf)Cl2 (28.6 mg, 39.1 μmol, 0.5 equiv), bis(pinacolato)diboron (B2pin2; 199 mg, 783 μmol, 10 equiv), toluene (0.36 mL) and N,N-dimethylformamide (DMF; 0.36 mL). The mixture was stirred at 80 °C for 18 h

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• heteroarenes with the CF3 radical through a Cu(I/II) catalytic cycle. In 2013, the Szabó [143] and Wang group [144] described the copper-mediated C–H trifluoromethylation of quinones with Togni’s reagent. Szabó utilized a stoichiometric amount of CuCN combined with catalytic bis(pinacolato)diboron, whereas

Calixazulenes: azulene-based calixarene analogues – an overview and recent supramolecular complexation studies

• Paris E. Georghiou,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Hidetaka Nishimura,
• Jaehyun Lee,
• Atsushi Wakamiya and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2018, 14, 2488–2494, doi:10.3762/bjoc.14.225

• Suzuki–Miyaura coupling reaction of bromobenzene with 5,7-di(Bpin)azulene, which in turn was formed via the exhaustive borylation of azulene with excess bis(pinacolato)diboron (B2pin2) [21]. Cyclocondensation of 5,7-diphenylazulene with formaldehyde produced 5 [22] under conditions similar to those used

Atom-economical group-transfer reactions with hypervalent iodine compounds

• Andreas Boelke,
• Peter Finkbeiner and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108

• utility is limited since it requires highly reactive boron compounds as nucleophiles. Symmetrical biphenyls 3’ can be generated from the corresponding symmetrically substituted diaryliodonium salts 1 and bis(pinacolato)diboron as demonstrated by Muñiz and co-workers [25]. In the first step, a mild carbon

Mechanochemical borylation of aryldiazonium salts; merging light and ball milling

• José G. Hernández

Beilstein J. Org. Chem. 2017, 13, 1463–1469, doi:10.3762/bjoc.13.144

• the original study, irradiation for 18 h of a MeCN solution of aryldiazonium salts, bis(pinacolato)diboron (B2pin2, 2) and eosin Y with a 25 W visible light lamp led to the corresponding arylboronates in moderate to good yields [18]. Results and Discussion To commence, a PMMA milling jar was designed

Synthesis of the heterocyclic core of the D-series GE2270

• Christophe Berini,
• Thibaut Martin,
• Pierrik Lassalas,
• Francis Marsais,
• Christine Baudequin and
• Christophe Hoarau

Beilstein J. Org. Chem. 2017, 13, 1407–1412, doi:10.3762/bjoc.13.137

• -chlorobithiazolylpyridine 7 in fair 68% yield over 2 steps. Next, the strict use of our previous protocol of BSC cross-coupling of methyl(4-bromothiazol-2-yl)ketone (8) with 6-chlorobithiazolylpyridine 7 [22] that employs bis(pinacolato)diboron (B2pin2) as borylating agent and Pd2(dba)3/Cy-JohnPhos pair as optimal catalyst

• , THF/H2O (2:1), rt, 14 h, 93%. e) (i) 8, Bis(pinacolato)diboron, Pd(OAc)2 (5 mol %), CyJohnPhos (20 mol %), KOAc, dioxane, 1 h; (ii) K3PO4, dioxane/H2O (4:1), 110 °C, 14 h, 82–99%. f) Lawesson’s reagent, CH2Cl2, 40 °C, 12 h, 91–94%. g) Ethyl bromopyruvate, CaCO3, THF/EtOH (1:1), 60 °C, 24 h. Synthesis

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

• (Scheme 1). The most commonly used boron sources are pinacolborane (HBpin, 1a) and bis(pinacolato)diboron (B2pin2, 1b), which form pinacol esters of arylboronic acids. Although the pinacol ester products prepared in these reactions are amenable to a range of transformations, their reactivity is generally

Copper-mediated arylation with arylboronic acids: Facile and modular synthesis of triarylmethanes

• H. Surya Prakash Rao and
• A. Veera Bhadra Rao

Beilstein J. Org. Chem. 2016, 12, 496–504, doi:10.3762/bjoc.12.49

• preparation of the starting diarylmethanol 20, which was accomplished by the addition the anion from 9-bromophenanthrene [63] 19 to 4-methoxybenzaldehdye. The resulting diarylmethanol 20 was treated with bis(pinacolato)diboron [64] 10n, which has an 2-nitrobenzyl protecting group on the phenolic hydroxy group

Chiral Cu(II)-catalyzed enantioselective β-borylation of α,β-unsaturated nitriles in water

• Lei Zhu,
• Taku Kitanosono,
• Pengyu Xu and
• Shū Kobayashi

Beilstein J. Org. Chem. 2015, 11, 2007–2011, doi:10.3762/bjoc.11.217

• chiral 2,2′-bipyridine ligand L for 1 h. After successive addition of cinnamonitrile (1a) and bis(pinacolato)diboron, the resulting mixture was stirred at room temperature for 12 h. Subsequent oxidation by treatment with NaBO3 was conducted to determine the enantioselectivity. The desired β

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• and least toxic choice. Though there are many examples of copper-catalyzed 1,4-additions of boron, most of the reports use bis(pinacolato)diboron (B2pin2) as a source of boron. In 2013, Molander and co-workers reported the asymmetric 1,4-addition of bisboronic acid (BBA) and tetrakis(dimethylamino

Clean and fast cross-coupling of aryl halides in one-pot

• Valerica Pandarus,
• Geneviève Gingras,
• François Béland,
• Rosaria Ciriminna and
• Mario Pagliaro

Beilstein J. Org. Chem. 2014, 10, 897–901, doi:10.3762/bjoc.10.87

• Unsymmetrically coupled biaryls are synthesized in high yield starting from different aryl bromides and bis(pinacolato)diboron by carrying out the Miyaura borylation reaction followed by the Suzuki–Miyaura reaction in the same reaction pot over 1–2 mol % SiliaCat DPP-Pd. The SiliaCat DPP-Pd catalyst is air-stable

• following Miyaura’s discovery from 1995. He demonstrated a direct route to boronic esters [2], namely the cross-coupling of bis(pinacolato)diboron (B2Pin2) with aryl or vinyl halides catalyzed by PdCl2(dppf) ([1,1′-bis(diphenylphosphino)ferrocene]palladium(II) dichloride) in the presence of excess KOAc at

• emerging as a promising tool for synthetic organic chemistry [9]. In this research context, we have recently described the heterogeneously catalyzed synthesis of boronic acid pinacol esters using a wide range of aryl chlorides, bromides and iodides and bis(pinacolato)diboron as borylating agent over the