Synthesis and anticancer activity of bis(2-arylimidazo[1,2-a]pyridin-3-yl) selenides and diselenides: the copper-catalyzed tandem C–H selenation of 2-arylimidazo[1,2-a]pyridine with selenium

• Mio Matsumura,
• Tsutomu Takahashi,
• Hikari Yamauchi,
• Shunsuke Sakuma,
• Yukako Hayashi,
• Tadashi Hyodo,
• Tohru Obata,
• Kentaro Yamaguchi,
• Yasuyuki Fujiwara and
• Shuji Yasuike

Beilstein J. Org. Chem. 2020, 16, 1075–1083, doi:10.3762/bjoc.16.94

Copper-based fluorinated reagents for the synthesis of CF₂R-containing molecules (R ≠ F)

• Louise Ruyet and
• Tatiana Besset

Beilstein J. Org. Chem. 2020, 16, 1051–1065, doi:10.3762/bjoc.16.92

• such copper-based reagents will be depicted and copper-catalyzed reactions are therefore beyond the scope of this review. Review Copper-based difluoromethylating reagents In this section the key advances made to access copper-based difluoromethylating reagents are summarized. The CF2H moiety [28][29

Accelerating fragment-based library generation by coupling high-performance photoreactors with benchtop analysis

• Quentin Lefebvre,
• Christophe Salomé and
• Thomas C. Fessard

Beilstein J. Org. Chem. 2020, 16, 982–988, doi:10.3762/bjoc.16.87

• reactions, and ranged from 6% to 50% for copper-catalyzed cross-coupling reactions [13]. Much information could be obtained from this screening. Electron-deficient aryl bromides led to better yields than neutral and electron-rich partners, as observed in previous reports on photochemically- or

Copper catalysis with redox-active ligands

• Agnideep Das,
• Yufeng Ren,
• Cheriehan Hessin and
• Marine Desage-El Murr

Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77

• ], and perform C–H functionalization through aerobic dearomatization of phenols [35]. These broad synthetic outcomes further led to a unified approach for the preparation of 1,2-oxy-aminoarenes by phenol–amine couplings (Scheme 10) [36]. We reported the formation of a C–N bond through copper-catalyzed

• in such systems in order to develop predictive tools for reactivity control [41]. Such knowledge is most likely to result in new advances in the fast-expanding field of redox catalysis. Copper complexes with amidophenolate type benzoxazole ligands for alcohol oxidations. Copper-catalyzed aerobic

• oxidation of alcohols and representative substrate scope. Introduction of H-bonding network in the ligand coordination sphere. Well-defined isatin copper complexes. Catalyst control in the biomimetic phenol ortho-oxidation. Structural diversity accessible by direct functionalization. Copper-catalyzed

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

• incorporating silicon or boron into new or existing drugs, in addition to their use as building blocks in cross-coupling reactions en route to various targets of both natural and unnatural origins. In this review, recent protocols relying on copper-catalyzed sp3 carbon–silicon and carbon–boron bond-forming

• interesting class of substrates for medicinal and polymer chemistry. Nevertheless, they can be transformed into a variety of building blocks for subsequent use in complex molecule synthesis. The first example of a copper-catalyzed C(sp3)–Si bond formation was reported by Oshima and co-workers in 1984 [25]. In

• bond formation Organoboron compounds are widely used in C–C and C–X (X = N, O) bond constructions. Straightforward methods for their synthesis involve the copper-catalyzed addition of organoboron compounds to alkynes, alkenes, and unsaturated carbonyl compounds, as well as the nucleophilic borylation

Towards the total synthesis of chondrochloren A: synthesis of the (Z)-enamide fragment

• Jan Geldsetzer and
• Markus Kalesse

Beilstein J. Org. Chem. 2020, 16, 670–673, doi:10.3762/bjoc.16.64

• formation of the (Z)-enamide should occur in a copper-catalyzed Buchwald-type reaction (Scheme 3). Based on a previous work of Buchwald and his group [13], we decided to use copper(I) iodide and N,N′-dimethylethylenediamine (DMEDA) as the catalytic system in THF, which was reported to be the solvent of

Copper-catalyzed O-alkenylation of phosphonates

• Nuria Vázquez-Galiñanes,
• Mariña Andón-Rodríguez,
• Patricia Gómez-Roibás and
• Martín Fañanás-Mastral

Beilstein J. Org. Chem. 2020, 16, 611–615, doi:10.3762/bjoc.16.56

• Feringa recently reported a catalytic method for the synthesis of mixed alkyl aryl phosphonates based on a copper-catalyzed arylation of phosphonates with diaryliodonium salts [32]. Encouraged by this work, in the context of an electrophilic alkenylation of phosphonates, we reasoned that the action of a

• groups, and final reductive elimination would form the new C(sp2)–O bond, providing an acyclic enol phosphonate with concomitant regeneration of the Cu(I) catalyst (Scheme 1b). Herein we report the successful realization of such a copper-catalyzed oxygen-alkenylation strategy and show that a range of

• , Table 1). We first run the reaction under the conditions reported for the copper-catalyzed O-arylation of phosphonates (CuCl as catalyst, 2,6-di-tert-butylpyridine (dtbpy) as additive in dichloromethane at 40 °C) [32]. Under those conditions, enol phosphonate 3a was the only product of the reaction

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• -tethered BODIPY derivatives serve as a substrate in the copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction, which is known as “click” reaction, allowing for a biological tissue labelling [35][36]. In addition, ethynyl-substituted BODIPYs yield unique π-conjugated BODIPY-based macrocycles by

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• definition and fails as a real “click” reaction. Although this cyclization reaction requires elevated temperatures and often yields both the 1,4- and 1,5-regioisomers, the Cu or Ru alkyne–azide cycloaddition falls exactly into the above definition [11]. In this respect, the copper-catalyzed cycloaddition

• suitable ligands [14]. Ligands serve to increase and modulate the reactivity of copper salts. In the first attempt, tris((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)amine (TBTA) considerably speds up the copper-catalyzed cyclization [15]. Many structurally diverse ligands, such as nitrogen-, phosphorus-, carbon

• -, oxygen-, and sulfur-containing ligands were investigated soon after the disclosure of the auxiliary effect of ligands on copper-catalyzed alkyne–azide cycloaddition reactions [16][17]. Heterogeneous catalysts are safer than their homogeneous counterparts. They also offer some advantages, such as the ease

Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands

• Shohei Mimura,
• Sho Mizushima,
• Yohei Shimizu and
• Masaya Sawamura

Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50

• , Sapporo, Hokkaido 001-0021, Japan 10.3762/bjoc.16.50 Abstract A chiral phenol–NHC ligand enabled the copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters. The phenol moiety of the chiral NHC ligand played a critical role in producing the enantiomerically enriched products. The

• ligand on the copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with hydrosilanes, placing a focus on (Z)-isomer substrates, which generally gave slightly lower enantiomeric excess with the chiral bisphosphines compared to the (E)-isomer substrates. Results and Discussion

• ongoing in our laboratory. Experimental A typical procedure for the copper-catalyzed enantioselective conjugate reduction (Table 1, entry 4; Table 2, entry 1): In a glove box, CuCl (1.5 mg, 0.015 mmol), L4⋅HBF4 (9.8 mg, 0.015 mmol), and LiOt-Bu (2.4 mg, 0.03 mmol) were placed in a vial containing a

Copper-catalyzed remote C–H arylation of polycyclic aromatic hydrocarbons (PAHs)

• Anping Luo,
• Min Zhang,
• Zhangyi Fu,
• Jingbo Lan,
• Di Wu and
• Jingsong You

Beilstein J. Org. Chem. 2020, 16, 530–536, doi:10.3762/bjoc.16.49

• substituted polycyclic aromatic hydrocarbons (PAHs) is a desired but challenging task. A copper-catalyzed C7–H arylation of 1-naphthamides has been developed by using aryliodonium salts as arylating reagents. This protocol does not need to use precious metal catalysts and tolerates wide variety of functional

• of our ongoing research on direct C–H bond functionalization [20][27][28][29], we herein represent a copper-catalyzed remote C–H arylation of PAHs with aryliodonium salts as arylating reagents (Scheme 1). This protocol is compatible with different PAH substrates including 1-naphthamides, phenanthrene

Controlling alkyne reactivity by means of a copper-catalyzed radical reaction system for the synthesis of functionalized quaternary carbons

• Goki Hirata,
• Yu Yamane,
• Naoya Tsubaki,
• Reina Hara and
• Takashi Nishikata

Beilstein J. Org. Chem. 2020, 16, 502–508, doi:10.3762/bjoc.16.45

• could suggest new aspects of alkyne transformations in a copper catalyzed alkyl radical reaction system. Substrate scope of 1 and 2. aConducted at 80 °C for 24 h in MeCN with CuBr (10 mol %), 1,10-Phen (20 mol %), Cs2CO3 (4.0 equiv), NaI (2.0 equiv), 1 (3.0 equiv) and 2 (1.0 equiv). Yields were

Recent advances in photocatalyzed reactions using well-defined copper(I) complexes

• Mingbing Zhong,
• Xavier Pannecoucke,
• Philippe Jubault and
• Thomas Poisson

Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42

• ) [25]. This copper-catalyzed photocatalytic reduction generated an aryl radical that was trapped with various allylating reagents. First, the phenyl radical generated from the corresponding diphenyliodonium salt was added to various allyl sulfones substituted in the 2-position. The products were

• 2012, Collins and co-workers described a copper-catalyzed photocyclization to synthesize [5]helicene (Scheme 29) [43]. Using the in situ-formed [Cu(I)(dmp)(xantphos)]BF4 (25 mol %) in the presence of iodine and propylene oxide as the oxidant system under visible light irradiation, [5]helicene was

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• (diphenylphosphino)-1,1'-binaphthyl (BINAP) with a greater π-density and sterically demanding groups, have been extensively used in catalytic reactions [94]. Wang et al. [95] reported a copper-catalyzed phosphorylation in the synthesis of an oxazolylindolylphosphine as shown in Scheme 18. The intermediate amide 97

Copper-promoted/copper-catalyzed trifluoromethylselenolation reactions

• Clément Ghiazza and
• Anis Tlili

Beilstein J. Org. Chem. 2020, 16, 305–316, doi:10.3762/bjoc.16.30

• -promoted and copper-catalyzed processes for the introduction of SeCF3 groups Copper(I) trifluoromethylselenolate complexes Copper(I) trifluoromethylselenolate was first prepared in 1985 by the group of Yagupolskii [12]. Then, CuSeCF3·DMF was tested in the trifluoromethylselenolation of (hetero)aryl iodides

• , this species is in an equilibrium with the −SeCF3 anion. As proposed by Hor and Weng, Deng and Xiao also suggested that CuSeCF3 was the active species in the mechanism. In 2016, the group of Rueping described a sequential copper-catalyzed selenocyanation of aryldiazonium salts, followed by

• . Trifluoromethylselenolation of diazoacetates and diazonium salts with Me4NSeCF3 by the group of Goossen. Trifluoromethylselenolation with ClSeCF3 by the group of Tlili and Billard. Trifluoromethylselenolation with TsSeCF3 by the group of Tlili and Billard. Copper-catalyzed synthesis of a selenylated analog 30 of Pretomanid

Copper-catalyzed enantioselective conjugate addition of organometallic reagents to challenging Michael acceptors

• Delphine Pichon,
• Jennifer Morvan,
• Christophe Crévisy and
• Marc Mauduit

Beilstein J. Org. Chem. 2020, 16, 212–232, doi:10.3762/bjoc.16.24

• Delphine Pichon Jennifer Morvan Christophe Crevisy Marc Mauduit Université de Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR – UMR 6226, F-35000 Rennes, France 10.3762/bjoc.16.24 Abstract The copper-catalyzed enantioselective conjugate addition (ECA) of organometallic

• -acyloxazolidinones, N-acylpyrrolidinones, amides, and N-acylpyrroles have been scarcely investigated in Cu ECA despite their usefulness for postfunctionalizations. This tutorial review aims to describe the early examples and recent advances in copper-catalyzed asymmetric conjugate additions of dialkylzinc, Grignard

• , or trialkylaluminium reagents toward those challenging substrates and their fruitful application in the total synthesis of natural products. Review Enantioselective conjugate addition to challenging Michael acceptors Copper-catalyzed ECA to α,β-unsaturated aldehydes Nowadays, β-substituted enals

Combination of multicomponent KA² and Pauson–Khand reactions: short synthesis of spirocyclic pyrrolocyclopentenones

• Riccardo Innocenti,
• Elena Lenci,
• Gloria Menchi and
• Andrea Trabocchi

Beilstein J. Org. Chem. 2020, 16, 200–211, doi:10.3762/bjoc.16.23

• . Following our interest to DOS as a synthetic strategy for the generation of molecular scaffolds according to a couple/pair approach [45][46][47], we reasoned to combine the copper-catalyzed ketone–amine–alkyne (KA2) multicomponent coupling reaction [48] with the Pauson–Khand cycloaddition as the pairing

• was achieved, suggesting a role of the aromatic ring in activating the alkyne towards the copper-catalyzed process (Table 1, entries 3 and 4), as previously reported in other works [54]. Use of cyclopentanone, thus varying the ring size of the cyclic ketone, resulted in the conversion to the title

Allylic cross-coupling using aromatic aldehydes as α-alkoxyalkyl anions

• Akihiro Yuasa,
• Kazunori Nagao and
• Hirohisa Ohmiya

Beilstein J. Org. Chem. 2020, 16, 185–189, doi:10.3762/bjoc.16.21

• . The synergistic palladium/copper-catalyzed reaction of aromatic aldehydes, allylic carbonates, and a silylboronate produces the corresponding homoallylic alcohol derivatives. This process involves the catalytic formation of a nucleophilic α-silyloxybenzylcopper(I) species and the subsequent palladium

• ) afforded the linear allylation product 3aa with complete regioselectivity. The symmetric secondary allylic carbonate was converted to the corresponding homoallylic alcohol derivative in 50% yield (3af). To gain understanding into the mechanism of this synergistic palladium/copper-catalyzed allylic cross

• summary, we developed an umpolung strategy for catalytically formed α-alkoxyalkyl anions from aromatic aldehydes for the use in allylic cross-coupling reactions. The synergistic palladium/copper-catalyzed reaction of aromatic aldehydes, allylic carbonates, and a silylboronate delivered the homoallylic

The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates

• Narasimhamurthy Rajeev,
• Toreshettahally R. Swaroop,
• Ahmad I. Alrawashdeh,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Seegehalli M. Anil,
• Kuppalli R. Kiran,
• Chandra,
• Paris E. Georghiou,
• Kanchugarakoppal S. Rangappa and
• Maralinganadoddi P. Sadashiva

Beilstein J. Org. Chem. 2020, 16, 159–167, doi:10.3762/bjoc.16.18

• methods for carbamothioates have been reported. These include reactions of chlorothioformates with amines [14], thiocarbonyl benzotriazoles with alcohols [15], copper-catalyzed reactions of α-substituted stannanes with carbamothioates [16], reactions of isothiocyanates with alcohols [6][17], and reactions

Halogen-bonding-induced diverse aggregation of 4,5-diiodo-1,2,3-triazolium salts with different anions

• Xingyu Xu,
• Shiqing Huang,
• Zengyu Zhang,
• Lei Cao and
• Xiaoyu Yan

Beilstein J. Org. Chem. 2020, 16, 78–87, doi:10.3762/bjoc.16.10

• candidates for XB donors, which is mainly due to the ease of preparation via a copper-catalyzed click reaction between azide and alkyne [38][39]. 1,2,3-Triazoles and 1,2,3-triazolium-based XB activators have been found applications in catalytic reactions [40][41] and anion recognition [42]. Recently, we

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

• László Orha,
• József M. Tukacs,
• László Kollár and
• László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

• important transformation. Herein we report a study on the palladium-catalyzed copper- and added base-free Sonogashira coupling reactions to synthesize various acetylenes in γ-valerolactone-based ionic liquids under mild conditions. Results and Discussion We recently demonstrated that copper-catalyzed

Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• catalytic hydrogenation to 4 followed by protection with TBDMS to give 5 in 63% yield for three steps. The synthesis of the other half of the photochrome started with bromination of difluorinated aniline to give 6 followed by copper-catalyzed cyanation to 7 in 62% overall yield. Diazonization of 7 with

• nitrosonium tetrafluoroborate gave 8 (54% yield). The two parts of the chromophore were coupled starting by treatment of 5 with n-butyllithium at −78 °C, which was coupled in situ with 8 to AB 9 (17% yield). Copper-catalyzed hydration of 9 gave amide 10, which was treated with TBAF to alcohol 11 in 42

Fluorinated maleimide-substituted porphyrins and chlorins: synthesis and characterization

• Valentina A. Ol’shevskaya,
• Elena G. Kononova and
• Andrei V. Zaitsev

Beilstein J. Org. Chem. 2019, 15, 2704–2709, doi:10.3762/bjoc.15.263

• 1,2,3-triazole heterocycles via the copper-catalyzed azide–alkyne cycloaddition reaction (CuAAC) between alkynes and azides, developed independently by Sharpless [41] and Meldal [42]. In addition to the applications of triazoles as pharmacophores in the potential biologically active molecules, these

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

• phase-transfer copper catalyst (Scheme 27). Notably, with 10 mol % of (IPr)CuOTf, full conversion can be accomplished in 10 minutes at 45 °C. Allylic fluorination: In 2013, there is an example of a copper-catalyzed fluorination of internal allylic bromides (Scheme 28). In Liu’s study, this approach was

• (Scheme 31a) [74]. Che and co-workers [75] achieved a similar α-fluorination of β-ketoesters and N-Boc-oxindoles (Scheme 31b). Compared with Du’s method, Che employed both AgClO4 and chiral iron(III)-salan complexes as the catalyst. In 2016, the group of Nishikata [76] described a copper-catalyzed site

• five and six-membered ring β-ketoesters were converted to the corresponding products in high yields and enantioselectivities (Scheme 56). In 2018, the first example for the copper-catalyzed stereospecific trifluoromethylation of secondary propargyl sulfonates was described by the group of Zhang [116