DDQ in mechanochemical C–N coupling reactions

• Shyamal Kanti Bera,
• Rosalin Bhanja and
• Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

• as C–P [17], C–O [18][19][20], and C–S [21] were achieved using DDQ as an oxidant [22][23]. In addition, the utilization of DDQ as a photoredox catalyst [24] and co-catalyst [25][26] have also been documented in organic synthesis [27]. DDQ-mediated oxidative C–N cross-coupling reactions are well

• direct C–H amination is vital to provide many amine derivatives by sustainable methods [36][37]. The dehydrogenative C–N cross-coupling reactions from unreactive N–H and C–H bonds can lead to various nitrogen-containing heterocycles [32][38]. Herein, we disclose the DDQ-mediated oxidative C–N coupling

• , followed by hydride abstraction to generate the desired product 2a. On the other hand, the formation of quinazolin-4(3H)-ones starts with the formation of an imine intermediate and then it will follow the similar mechanistic pathway. To explore the synthetic utility of the oxidative C–N cross-coupling

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

Chan–Evans–Lam N1-(het)arylation and N1-alkеnylation of 4-fluoroalkylpyrimidin-2(1H)-ones

• Viktor M. Tkachuk,
• Oleh O. Lukianov,
• Mykhailo V. Vovk,
• Isabelle Gillaizeau and
• Volodymyr A. Sukach

Beilstein J. Org. Chem. 2020, 16, 2304–2313, doi:10.3762/bjoc.16.191

• products, in contrast to the 4-methyl and 4-unsubstituted substrates which do not undergo N1-arylation under similar reaction conditions. Keywords: C–N cross-coupling; Chan–Evans–Lam reaction; pyrimidin-2(1Н)-ones; fluoroalkyl group; boronic acids; Introduction The catalytic formation of C–N bonds in the

• uniquely advantageous means to perform C–N cross-coupling reactions [15][16][17]. The corresponding Ullmann-type reaction currently known as Chan–Evans–Lam (CEL) coupling is characterized by the combination of two nucleophilic reactants which implies that oxidative processes with atmospheric oxygen play a

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

• findings on C–N cross-coupling conditions. In these works, nickel-photoredox-catalyzed cross-couplings were the most successful with success rates up to 50% [10]. This was an improvement from non-photocatalyzed conditions, where success rates of 11–33% were observed for palladium-catalyzed cross-coupling

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

• the past few years [57]. Recently, Buchwald and Castillo have reviewed the exceptional utility of Pd-catalyzed C–N cross-coupling reactions for the preparation of anilines and aniline derivatives [58]. In many of the reactions, palladium was used along with a co-catalyst to enhance its catalytic

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• better yields and easier catalyst recover [26] than traditional processes. Lipshutz and co-workers have successfully exploited micelles not only as nanoreactors, but as an outstanding platform for achieving greener organic reactions [26][65][66]. They have shown, for example, C–N cross-coupling reactions

Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C–S cross-coupling reaction

• Debasish Sengupta,
• Koushik Bhowmik,
• Goutam De and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 1796–1806, doi:10.3762/bjoc.13.174

• used in C−C or C−N cross-coupling reactions [44][45][46][47]. We have recently shown that uniformly dispersed Ni NPs that are free of agglomeration can be embedded in RGO sheets (Ni/RGO). This very stable Ni/RGO nanocomposite enhances the reduction rate of Cr(VI) species to Cr(III) in the presence of

TBHP-mediated highly efficient dehydrogenative cross-oxidative coupling of methylarenes with acetanilides

• Cui Chen,
• Weibing Liu and
• Peng Zhou

Beilstein J. Org. Chem. 2016, 12, 2250–2255, doi:10.3762/bjoc.12.217

• ketoximes [13], the C–N cross coupling between aromatic amides or amines and aryl(pseudo)halides [14][15] or aldehydes [16][17][18][19][20]. However, to the best of our knowledge, the studies of dehydrogenative cross-oxidative-coupling reactions between methylarenes and amines for the formation of amides

Enantioconvergent catalysis

• Justin T. Mohr,
• Jared T. Moore and
• Brian M. Stoltz

Beilstein J. Org. Chem. 2016, 12, 2038–2045, doi:10.3762/bjoc.12.192

• generation of radical intermediates from chiral sp3-hybridized halides presents another opportunity for type II enantioconvergent catalysis. Peters and Fu have reported a system for the Cu-catalyzed C–N cross-coupling of racemic tertiary alkyl halide electrophiles with carbazole nucleophiles induced by

Studies on the synthesis of peptides containing dehydrovaline and dehydroisoleucine based on copper-mediated enamide formation

• Franziska Gille and
• Andreas Kirschning

Beilstein J. Org. Chem. 2016, 12, 564–570, doi:10.3762/bjoc.12.55

• moieties present in the antibiotic myxovalargin is reported. Peptide formation is based on a copper-mediated C–N cross-coupling protocol between an acyl amide and a peptidic vinyl iodide. The presence of a neighboring arginine in the vinyl iodide posed a challenge with respect to the choice of the

• protecting group and the reaction conditions. It was found that ornithine – a suitable precursor – is better suited than arginine for achieving good yields for the C–N cross-coupling reaction. The optimized conditions were utilized for the synthesis of peptides 32, 33, 39 and 40 containing a neighboring

• , Alloc = allyloxycarbonyl, Boc = tert-butyloxycarbonyl, Pbf = 2,2,4,6,7-pentamethyldihydrobenzofurane-5-sulfonyl). Copper-mediated C–N cross-coupling of dehydropeptides 31–33, 36, 37, and 39–41. C–N coupling reaction between amide 43 and vinyl iodide 42; formation of dehydroisoleucine containing peptide

Copper catalysis in organic synthesis

• Sherry R. Chemler

Beilstein J. Org. Chem. 2015, 11, 2252–2253, doi:10.3762/bjoc.11.244

• field of copper-catalysis from 7 countries make up this Thematic Series, “Copper catalysis in organic synthesis”. Contributions include authoritative reviews on the latest developments in copper-catalyzed Click applications, C–N cross-coupling, C–H functionalization, trifluoromethylations, asymmetric

• . Depending on its oxidation state, this metal can efficiently catalyze reactions involving both one and two-electron (radical and polar) mechanisms, or both. Copper coordinates easily to heteroatoms and to π-bonds and is well-known to activate terminal alkynes. The Ullman and Goldberg C–C and C–N cross

• -coupling reactions were discovered over a century ago and their development has really blossomed over the past twenty years. Second, copper is an earth-abundant metal, making its use more cost effective and more sustainable than precious transition metal catalysts. Over 25 contributions from leaders in the

Recent advances in copper-catalyzed C–H bond amidation

• Jie-Ping Wan and
• Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

• chloride/anhydrides [6][7][8][9][10][11], nitrile hydrolysis [12][13][14][15][16], Goldberg C–N cross coupling reaction [17], aldehyde/ketone amidation [18][19][20][21][22][23], the transamidation [24][25][26][27][28][29], and oxime rearrangement [30][31][32][33], to name only a few. It is obvious that the

An intramolecular C–N cross-coupling of β-enaminones: a simple and efficient way to precursors of some alkaloids of Galipea officinalis

• Hana Doušová,
• Radim Horák,
• Zdeňka Růžičková and
• Petr Šimůnek

Beilstein J. Org. Chem. 2015, 11, 884–892, doi:10.3762/bjoc.11.99

• leading to the above-mentioned tetrahydroquinoline moiety. The methodology is superior to the methods published to date. Keywords: C–N cross-coupling; copper; enaminone; palladium; tetrahydroquinoline; Introduction Galipea officinalis Hancock is a Venezuelan shrub, the bark (angostura bark) of which is

• catalytic hydrogenation of the corresponding quinolones 2 (Scheme 2) with yields not greater than 43%. In the present work, we introduce a quite different approach to the exocyclic enaminones 1 based on an intramolecular C–N cross-coupling of enaminones 3 (Scheme 2). Results and Discussion The synthesis of

• ) indicates the presence of an intramolecular hydrogen bond N–H···O. The enaminones 3 therefore possess Z configuration on the C=C bond. The intramolecular C–N cross-coupling β-Enaminones and related polarized ethylenes (generally enamines substituted by EWG on β-carbon atom) belong among the rather neglected

Phosphinate-containing heterocycles: A mini-review

• Olivier Berger and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2014, 10, 732–740, doi:10.3762/bjoc.10.67

• . Tandem Kabacknik–Fields/C–N cross-coupling reaction. Tandem Kabacknik–Fields/C-P cross-coupling reaction. Heterocyclization via amide formation. Cyclization via reductive amination. H-Phosphinate alkylation. Cyclization through intramolecular Michael addition. Double Arbuzov reaction of bis

Palladium-catalyzed C–N and C–O bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols

• Rajendra Surasani,
• Dipak Kalita,
• A. V. Dhanunjaya Rao and
• K. B. Chandrasekhar

Beilstein J. Org. Chem. 2012, 8, 2004–2018, doi:10.3762/bjoc.8.227

• .8.227 Abstract Simple and efficient procedures for palladium-catalyzed cross-coupling reactions of N-substituted 4-bromo-7-azaindole (1H-pyrrole[2,3-b]pyridine), with amides, amines, amino acid esters and phenols through C–N and C–O bond formation have been developed. The C–N cross-coupling reaction of

• dioxane was found to be crucial for all the C–N cross-coupling reactions. However, different Pd-catalyst precursors were used for different amines/amides and amino acid esters. We have enhanced the methodology towards the C–O-bond formation with various phenols, which is very difficult to achieve. K2CO3

New efficient ligand for sub-mol % copper-catalyzed C–N cross-coupling reactions running under air

• Per-Fredrik Larsson,
• Peter Astvik and
• Per-Ola Norrby

Beilstein J. Org. Chem. 2012, 8, 1909–1915, doi:10.3762/bjoc.8.221

• for sub-mol % copper-catalyzed C–N cross-coupling reactions. The efficiency of the ligand was determined by kinetic methods. DMDETA proved to display efficiency similar to DMEDA and, in addition, the resulting catalyst was tolerant to air. Keywords: copper; cross coupling; hyperactivity; kinetics

• could be involved in the mass transfer of the heterogeneous base. Conclusion In summary, a new and efficient ligand (DMDETA) for sub-mol % copper-catalyzed C–N cross coupling has been synthesized and evaluated in kinetic studies. DMDETA, together with DMEDA, is one of the few reported ligands that work

Directed ortho,ortho'-dimetalation of hydrobenzoin: Rapid access to hydrobenzoin derivatives useful for asymmetric synthesis

• Inhee Cho,
• Labros Meimetis,
• Lee Belding,
• Michael J. Katz,
• Travis Dudding and
• Robert Britton

Beilstein J. Org. Chem. 2011, 7, 1315–1322, doi:10.3762/bjoc.7.154

• diiodohydrobenzoin 12 in Cu-catalyzed C–N cross-coupling reactions [33] led only to the formation of cis-4b,9b-dihydrobenzofuro[3,2-b]benzofuran (24) [34]. Consequently, the diol 12 was converted to the corresponding acetonide 25 or methyl ether 26 prior to cross-coupling. In this manner, the diphenylhydrobenzoin