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

• through subsequent C–C bond formation (Scheme 72) [135]. The proposed mechanism involves the formation of L–Cu–O–t-Bu 458 which reacts with B2pin2 to generate L-Cu-Bpin 459. The subsequent coordination to the aldehyde results in the intermediate 461. Upon protonation of 461 the desired enantiomerically

• an appropriate electrophile led to C–C bond formation, ultimately delivering chiral tertiary alcohols. Mechanistic studies and DFT calculations showed that an in situ-formed borylcopper(I) species is responsible for the 1,2-addition (Scheme 73) [136]. C,O-Diboration of ketones 464 was explored using

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

• , while an achiral NHC/copper catalyst has successfully been utilized in this reaction [13]. Meanwhile, we devoted our effort to develop novel enantioselective C–C bond formation reactions utilizing chiral phenol–NHC/copper catalyst systems [14][15][16][17][18], in which the phenol group of the NHC ligand

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

• Pd-catalyzed cascade reaction (C–C bond formation/C–H cyclization process) of N-arylpropynamide 4 for the preparation of indolinone derivatives 5 was previously reported by Li’s group [34][35]. In another report on C–H cyclization by Lei’s group, Ni-catalyzed aromatic C–H alkylation occurs via a

KOt-Bu-promoted selective ring-opening N-alkylation of 2-oxazolines to access 2-aminoethyl acetates and N-substituted thiazolidinones

• Qiao Lin,
• Shiling Zhang and
• Bin Li

Beilstein J. Org. Chem. 2020, 16, 492–501, doi:10.3762/bjoc.16.44

• to synthesize thiazolidinone derivatives through a Barton–McCombie pathway in 2015 [17] (Scheme 1b). Recently, potassium tert-butoxide has been shown to be an efficient promoter for C–C-bond formation reactions [18][19][20][21][22]. However, only few reports described C–N-bond cross-coupling

Visible-light-induced addition of carboxymethanide to styrene from monochloroacetic acid

• Kaj M. van Vliet,
• Nicole S. van Leeuwen,
• Albert M. Brouwer and
• Bas de Bruin

Beilstein J. Org. Chem. 2020, 16, 398–408, doi:10.3762/bjoc.16.38

• of photoredox catalytic C–C bond formation, its application in the field of atom transfer radical addition (ATRA) reactions is very important. Remarkably, this type of C–C bond formation became only popular in 2011, while the first example was already published by Barton in 1994 [28]. Recently

• contains a carboxyl group that could perhaps be oxidatively decarboxylated to generate a chloromethyl radical. In this study, we investigated the possibility of redox neutral, visible light photoredox catalyzed C–C bond formation with monochloroacetic acid. Results and Discussion First, we used cyclic

Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst

• Abhijit Paul,
• Debnath Chatterjee,
• Srirupa Banerjee and
• Somnath Yadav

Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16

• recovered catalyst to TEM and TEM–SAED analysis (Figures S12 and S13, Supporting Information File 1) and found that it remained consistent with “fresh” RuNC. Homogeneous vs heterogeneous mechanism of catalysis The actual nature of the catalytic species in metal nanoparticle-catalysed C–C bond formation

Extension of the 5-alkynyluridine side chain via C–C-bond formation in modified organometallic nucleosides using the Nicholas reaction

• Renata Kaczmarek,
• Dariusz Korczyński,
• James R. Green and
• Roman Dembinski

Beilstein J. Org. Chem. 2020, 16, 1–8, doi:10.3762/bjoc.16.1

• confirmed that the Nicholas reaction can be carried out in a nucleoside presence, leading to a divergent synthesis of novel metallo-nucleosides enriched with alkene, arene, arylketo, and heterocyclic functions, in the deoxy and ribo series. Keywords: alkynes; 5-alkynyluridines; C–C-bond formation; dicobalt

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

• wide applicability from syntheses of common building blocks to agrochemicals, just to name a few advantages [4][5][6]. From the series of palladium-assisted C–C bond formation, the Sonogashira coupling reaction has been identified as a viable synthetic method for the preparation of various alkenyl- and

Indium-mediated C-allylation of melibiose

• Christian Denner,
• Manuel Gintner,
• Hanspeter Kählig and
• Walther Schmid

Beilstein J. Org. Chem. 2019, 15, 2458–2464, doi:10.3762/bjoc.15.238

• the elongated unit at the reducing end of the disaccharide. Keywords: carbohydrates; C–C bond formation; indium-mediated allylation; melibiose; ozonolysis; Introduction The tin and indium-mediated allylation (IMA) proved to be useful synthetic tools for the chain elongation of unprotected

Characterization of two new degradation products of atorvastatin calcium formed upon treatment with strong acids

• Jürgen Krauß,
• Monika Klimt,
• Markus Luber,
• Peter Mayer and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2085–2091, doi:10.3762/bjoc.15.206

• /dehydration process in the side chain), treatment with conc. aqueous hydrochloric acid gave a complex, bridged molecule under C–C-bond formation of the lactone moiety with the pyrrole, migration of the isopropyl group and loss of the carboxanilide residue. The novel degradation products were characterized by

Regioselective Pd-catalyzed direct C1- and C2-arylations of lilolidine for the access to 5,6-dihydropyrrolo[3,2,1-ij]quinoline derivatives

• Hai-Yun Huang,
• Haoran Li,
• Thierry Roisnel,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2019, 15, 2069–2075, doi:10.3762/bjoc.15.204

• methodology provides a straightforward access to several lilolidine derivatives from commercially available compounds via one, two or three C–H bond functionalization steps allowing to tune their biological properties. Keywords: catalysis: C–C bond formation; C–H bond activation; lilolidine; palladium

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• organic processes and have attracted considerable interest in this regard. Ru has efficiently catalyzed C–H activation reactions for C–C bond formation, aza-Michael reactions and many more MCRs [27][76][77]. During the writing of this review, we came through the fact that ruthenium catalysts were mostly

Diazocine-functionalized TATA platforms

• Roland Löw,
• Talina Rusch,
• Fynn Röhricht,
• Olaf Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1485–1490, doi:10.3762/bjoc.15.150

• bromotoluene 3 with TMS-protected acetylene 4 (95%). The C–C bond formation of 5 and 6 to give dibenzoyl 7 was achieved with potassium butoxide and elemental bromine (9%) according to a literature procedure [27]. The para-ethynyldiazocine 8 was obtained by reduction of both nitro groups, followed by oxidation

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

• Alexander N. Reznikov,
• Anastasiya E. Sibiryakova,
• Marat R. Baimuratov,
• Eugene V. Golovin,
• Victor B. Rybakov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127

• ; Michael addition; nickel complexes; nitroalkenes; Introduction Sulfones are widely used in organic synthesis, particularly, in various reactions of C–C and C=C-bond formation [1][2][3][4]. The use of sulfones in Julia–Kocienski [1] and Ramberg–Bäcklund reactions [2] made this class of compounds

Alkylation of lithiated dimethyl tartrate acetonide with unactivated alkyl halides and application to an asymmetric synthesis of the 2,8-dioxabicyclo[3.2.1]octane core of squalestatins/zaragozic acids

• Herman O. Sintim,
• Hamad H. Al Mamari,
• Hasanain A. A. Almohseni,
• Younes Fegheh-Hassanpour and
• David M. Hodgson

Beilstein J. Org. Chem. 2019, 15, 1194–1202, doi:10.3762/bjoc.15.116

• viability of the rest of sequence outlined in Scheme 2 from an alkylated tartrate. While further C–C bond formation by enolate formation at the remaining methine on a monoalkylated tartrate acetonide had been reported by Molander and Harris [29], and by Kelly and co-workers [30]; the question whether such

Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation

• Sebastian Haferkamp,
• Andrea Paul,
• Adam A. L. Michalchuk and
• Franziska Emmerling

Beilstein J. Org. Chem. 2019, 15, 1141–1148, doi:10.3762/bjoc.15.110

• reaction environment. It was subsequently demonstrated how a combination of different in situ methods can provide more thorough investigation of mechanochemical reaction mechanisms [14][15][16]. Of particular benefit to synthetic reactions, such as C–C bond formation [17][18], the use of Raman spectroscopy

Switchable selectivity in Pd-catalyzed [3 + 2] annulations of γ-oxy-2-cycloalkenones with 3-oxoglutarates: C–C/C–C vs C–C/O–C bond formation

• Yang Liu,
• Julie Oble and
• Giovanni Poli

Beilstein J. Org. Chem. 2019, 15, 1107–1115, doi:10.3762/bjoc.15.107

• transient η2-alkene complex A (steps a and b). Deprotonation of the pro-nucleophile 1a by the counter-anion of the η3-allyl-Pd complex exchanges the benzoate for the enolate anion (step c) [50], and following C–C bond formation from the resulting anion-scrambled complex C leads to the Pd(0) complex D (step

Oxidative radical ring-opening/cyclization of cyclopropane derivatives

• Yu Liu,
• Qiao-Lin Wang,
• Zan Chen,
• Cong-Shan Zhou,
• Bi-Quan Xiong,
• Pan-Liang Zhang,
• Chang-An Yang and
• Quan Zhou

Beilstein J. Org. Chem. 2019, 15, 256–278, doi:10.3762/bjoc.15.23

• introduced the Na2S2O8-promoted ring-opening/alkynylation of cyclopropanols 91 with ethynylbenziodoxolones (EBX) 116 for the synthesis of the alkynylated ketones 117 (Scheme 27) [107]. This reaction involved a C–C bond cleavage, radical rearrangement, and C–C bond formation, and showed a wide substrates

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• (SM) cross-coupling reaction is also considered as one of the most versatile methods for C–C bond formation [8][9][10][11][12]. Application of a wide range of organometallic reagents (e.g., organoboron reagents) are possible due to their commercial availability. Owing to the mild reaction conditions

• summarized various approaches to a wide range of carbocycles and heterocycles that deals with a strategic utilization of SM coupling and metathesis as key steps. Interestingly, application of these two powerful methods in combination for a C–C bond formation process shorten the synthesis sequence for the

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• , considerable attention has been focused on the development of the catalytic fixation of CO2 via carbon–carbon (C–C) bond formation using a variety of organic compounds as starting materials [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. A key factor for the successful catalytic fixation of CO2 is

• a). Subsequently, the reductive elimination of methane from B yields the low-valent allyl-Co(I) species C (step b). Then, C–C bond formation at the γ-position occurs via a reaction with CO2, affording the carboxylate Co species D (step c). Finally, a linear carboxylated product is obtained by the

• importance, since the highly reactive intermediate can be generated by photochemical reaction such as electron transfer and energy transfer [43][44][45]. Among them, light-energy-driven CO2 fixation reactions via C–C bond formation are promising in terms of mimicking photosynthesis. In 2015, Murakami et al

Practical tetrafluoroethylene fragment installation through a coupling reaction of (1,1,2,2-tetrafluorobut-3-en-1-yl)zinc bromide with various electrophiles

• Ken Tamamoto,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2018, 14, 2375–2383, doi:10.3762/bjoc.14.213

• ), which can efficiently construct a new C–C bond [30][31][32]. Thus, we aimed at the development of an efficient preparation of a thermally stable organozinc reagent, possessing a CF2CF2 fragment as a thermally stable tetrafluoroethylenating agent, and successive C–C bond formation to produce a wide

• tetrafluoroethyllithium [12][25] and -magnesium species [22][23]. The synthetic uses of 2-Zn as a promising tetrafluorinating agent were tested in several reactions. First, we demonstrated a typical C–C bond formation reaction. Treating freshly prepared 2-Zn (ca. 0.70 M in DMF) with 5.0 equiv of iodobenzene (3a) in the

A challenging redox neutral Cp*Co(III)-catalysed alkylation of acetanilides with 3-buten-2-one: synthesis and key insights into the mechanism through DFT calculations

• Andrew Kenny,
• Alba Pisarello,
• Arron Bird,
• Paula G. Chirila,
• Alex Hamilton and
• Christopher J. Whiteoak

Beilstein J. Org. Chem. 2018, 14, 2366–2374, doi:10.3762/bjoc.14.212

• energy difference between the C–H activation and C–C bond formation steps makes identification of the rate limiting step difficult by DFT calculations alone, however, parallel kinetic isotope effect (KIE) experiments do suggest that the C–H activation step is not rate limiting (KIE = 1.3), which is not

Hydroarylations by cobalt-catalyzed C–H activation

• Rajagopal Santhoshkumar and
• Chien-Hong Cheng

Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202

• found intermolecular kinetic isotope effect (KIE) of kH/kD = 2.1 and H/D crossover studies strongly suggest that the reaction proceeds through an oxidative addition of a C–H bond to low-valent cobalt followed by alkyne insertion and reductive elimination. Furthermore, the new C–C bond formation occurred

Cobalt-catalyzed nucleophilic addition of the allylic C(sp³)–H bond of simple alkenes to ketones

• Tsuyoshi Mita,
• Masashi Uchiyama,
• Kenichi Michigami and
• Yoshihiro Sato

Beilstein J. Org. Chem. 2018, 14, 2012–2017, doi:10.3762/bjoc.14.176

• involving catalytic C–C bond construction with the double bond of terminal alkenes (e.g., Heck reaction, hydrometalation followed by functionalization, carbometalation, and olefin metathesis) [10][11][12][13]. However, direct C–C bond formation of the allylic C(sp3)–H bond adjacent to double bonds has

• -catalyzed C–C bond formation using a stoichiometric amount of an oxidant [16][17][18][19][20][21][22], the π-allylpalladium intermediate [23][24][25] is an electrophilic species that exclusively reacts with nucleophiles. Therefore, it would be a formidable challenge for the generation of a nucleophilic π

• would lead to a low-valent allylcobalt(I) species, and then C–C bond formation of IV with 2a would proceed at the γ-position to produce cobalt alkoxide(I) V [28][29][31][32][33][34][35][36][37][38][39]. Transmetalation between V and AlMe3 would furnish branched aluminium alkoxide VI along with the

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• found Taran’s suggestion as the most plausible because of the lowest activation free energy (ΔG‡ = 25.4 kcal·mol−1) and due to the observed 1,4-regiocontrol. Intrinsic reaction coordinate (IRC) calculations also showed concerted but asynchronous formation of the pyrazole ring, through initial C–C bond

• formation followed by Cu–N dissociation and C–N bond formation. Experiments performed in t-BuOD/D2O [119] also showed almost exclusive (>98:2) deuteration of position 3 in the final pyrazole ring. This finding supports the idea of Cu(I)-acetylide addition to give 3-metalated pyrazole (Cu-pyrazolide) that is