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

• phenanthridinones produced, the authors were able to quickly afford novel fagaronine 117j and nitidine 117k derivatives. Rhodium-catalyzed reactions In 2002, the Lautens laboratory reported a tandem cyclization of arylboronate esters 118 with a variety of bicyclic alkenes 15 using a water-soluble Rh-catalytic

NaI/PPh₃-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

• Dan Liu,
• Yue Zhao and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

• disclosed a visible light-mediated radical tandem cyclization of N-arylacrylamides with N-(acyloxy)phthalimides to access 3,3-dialkylated oxindoles in the presence of [Ru(bpy)3Cl2]·6H2O [46]. However, these seminal methods remain limited by the need of noble-metal-based photocatalysts, excess additives and

Cathodic generation of reactive (phenylthio)difluoromethyl species and its reactions: mechanistic aspects and synthetic applications

• Sadanobu Iwase,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2022, 18, 872–880, doi:10.3762/bjoc.18.88

• bearing a perfluoroalkyl or perfluoroacyl group [27][28][29][30]. Furthermore, they extended this methodology to tandem cyclization to provide fused difluoromethylene-containing heterocycles [31]. In consideration of these facts, we studied the cathodic reduction of 1 using a mediator. Indirect cathodic

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

• reported [53]. In 2015, Kang and co-workers described a FeCl2-catalyzed tandem cyclization/cross-coupling reaction of alkyl iodides 1 with aryl Grignard reagents 2 to give arylmethyl-substituted pyrrolidines and tetrahydrofurans 3 in poor to excellent yield (Scheme 3) [54]. The concept of alkyl halide

• byproducts were detected which supports the absence of an initial oxidative addition between the alkyl iodide and the active Fe catalyst. The possibility of a radical process rather than ionic cross-coupling is supported by the tandem cyclization/cyclopropyl ring-opening reaction, similar to previous reports

Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

• Yi Liu,
• Puying Luo,
• Yang Fu,
• Tianxin Hao,
• Xuan Liu,
• Qiuping Ding and
• Yiyuan Peng

Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163

• in Scheme 22). Conclusion 1,3-Enynes, one of the most significant classes of Michael acceptors for the construction of N-heterocycles, have been widely used in organic synthesis. We herein reviewed the recent advances in the development of tandem cyclization reactions of 1,3-enynes in the presence of

• electrophiles or Lewis acid catalysts to form pyridines and pyrroles. Series of iodinated, aminated, selenylated, sulfenylated, esterified, and hydroxylated pyridine derivatives have been prepared based on 1,3-enynes. In addition, we also reviewed the tandem cyclization of 1,3-enynes to realize various

• halogenation of 2-trifluoromethyl-1,3-enynes to pyrroles. Copper-catalyzed cascade cyclization of 2-nitro-1,3-enynes with amines. Tandem cyclization of 2-nitro-1,3-enynes, Togni reagent II, and amines. Tandem cyclization of 2-nitro-1,3-enynes, TMSN3, and amines. Cascade cyclization of 6-hydroxyhex-2-en-4-ynals

Helicene synthesis by Brønsted acid-catalyzed cycloaromatization in HFIP [(CF₃)₂CHOH]

• Takeshi Fujita,
• Noriaki Shoji,
• Nao Yoshikawa and
• Junji Ichikawa

Beilstein J. Org. Chem. 2021, 17, 396–403, doi:10.3762/bjoc.17.35

• can be successfully applied to cyclization at multiple reaction sites. By using bisacetals bearing a naphthalene core (Ar2) as substrates, tandem cyclization achieved the efficient synthesis of several ortho-fused six-hexagon benzenoids [21]. On the basis of our work mentioned above, we assumed that

• types of helicenes using a sequence of (i) Suzuki–Miyaura coupling of acetal-containing components and (ii) catalytic cycloaromatization with the aid of a cation-stabilizing fluoroalcohol, HFIP, as solvent. Particularly, helicene synthesis using tandem cyclization of bisacetals with teraryl structures

Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties

• Liliia Moshniaha,
• Marika Żyła-Karwowska,
• Joanna Cybińska,
• Piotr J. Chmielewski,
• Ludovic Favereau and
• Marcin Stępień

Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81

• difference is much smaller in the α-free analogues cNMI3H and cNMI2H (ca. 0.1 V). Conclusion The present work shows that the tandem cyclization–oxygenation reaction is a general strategy for the synthesis of low-bandgap bipyrrole boomerangs and is applicable to targets with variable donor–acceptor character

Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis

• Zhen Cao,
• Aline Lacoudre,
• Cybille Rossy and
• Brigitte Bibal

Beilstein J. Org. Chem. 2019, 15, 2465–2472, doi:10.3762/bjoc.15.239

• %) efficiently catalyzed the intramolecular cyclization with 65–92% yields (Table 1, entries 3–7). To our delight, the transformation also reached 92% yield by employing 1a at 0.5 mol % (Table 1, entry 4). Compared to literature [60][61][62], catalyst 1a is effective for the tandem cyclization of 2

Synthesis of benzo[d]imidazo[2,1-b]benzoselenoazoles: Cs₂CO₃-mediated cyclization of 1-(2-bromoaryl)benzimidazoles with selenium

• Mio Matsumura,
• Yuki Kitamura,
• Arisa Yamauchi,
• Yoshitaka Kanazawa,
• Yuki Murata,
• Tadashi Hyodo,
• Kentaro Yamaguchi and
• Shuji Yasuike

Beilstein J. Org. Chem. 2019, 15, 2029–2035, doi:10.3762/bjoc.15.199

• Ar(aryl)–Se bonds [9][10][11][12][13]. Various metals, such as Pd, Ni, Fe, and Cu have been used to catalyze the reactions of a Se source with aryl donors. Among these, Cu-catalyzed tandem cyclization via a one-step Ullmann-type Se-arylation and Csp2–H selenation are efficient methods for

• group having bromine to generate the tetracyclic target molecule. Conclusion Benzo[d]imidazo[2,1-b]benzoselenoazoles were prepared via Cs2CO3-mediated tandem cyclization followed by reaction of 1-(2-bromoaryl)benzimidazoles with Se powder without a transition metal catalyst. The molecular structure of

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

Intramolecular cascade annulation triggered by rhodium(III)-catalyzed sequential C(sp²)–H activation and C(sp³)–H amination

• Liangliang Song,
• Guilong Tian,
• Johan Van der Eycken and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 571–576, doi:10.3762/bjoc.15.52

• intramolecular migratory insertion affords intermediate C. Reductive elimination and subsequent oxidative addition give intermediate D. Then two pathways are involved in the following steps. In the main pathway (path a), intermediate D undergoes β-H elimination and tandem cyclization to give product 3a and Rh–H

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

• cyclization under transition-metal free conditions. With the addition of a radical scavenger such as TEMPO or BHT, the reaction was suppressed remarkably. In the same year, Dai’s group also reported the ring-opening-initiated tandem cyclization of cyclopropanols 91 with acrylamides 122 or 2-isocyanobiphenyls

• ring-opening and chlorination of cyclopropanols with aldehydes. Ag(I)-catalyzed ring-opening/alkynylation of cyclopropanols with EBX. Na2S2O8-promoted ring-opening/alkylation of cyclopropanols with acrylamides. Cyclopropanol ring-opening initiated tandem cyclization with acrylamides or 2

Synthesis of 2-trifluoromethylpyrazolo[5,1-a]isoquinolines via silver triflate-catalyzed or electrophile-mediated one-pot tandem reaction

• Xiaoli Zhou,
• Meiling Liu,
• Puying Luo,
• Yingjun Lai,
• Tangtao Yang and
• Qiuping Ding

Beilstein J. Org. Chem. 2014, 10, 2286–2292, doi:10.3762/bjoc.10.238

• Gynecology, Jiangxi Provincial people's Hospital, Nanchang, Jiangxi 330006, P. R. China 10.3762/bjoc.10.238 Abstract An efficient one-pot tandem cyclization/[3 + 2] cycloaddition reaction of N’-(2-alkynylbenzylidene)hydrazides with ethyl 4,4,4-trifluorobut-2-ynoate under silver triflate-catalyzed or

• of this tandem cyclization/[3 + 2] cycloaddition reaction, a range of N’-(2-alkynylbenzylidene)hydrazides 1a–j were prepared from the corresponding aldehydes and applied to the synthesis of trifluoromethylated pyrazolo[5,1-a]isoquinoline derivatives 3 under the optimized conditions (Table 1, entry 8

• -coupling reaction. Conclusion In conclusion, we have developed an efficient one-pot tandem cyclization/[3 + 2] cycloaddition reaction of N’-(2-alkynylbenzylidene)hydrazides with ethyl 4,4,4-trifluorobut-2-ynoate under silver triflate-catalyzed or electrophiles-mediated conditions. Highly functionalized

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• been reported [59]. Preformed 2-(1-alkynyl)arylaldimines 27 have been used in a MCR involving tandem cyclization/three-component reactions with diazo compounds 37 and water or alcohols 38 in the presence of dirhodium acetate and silver triflate cooperative catalysis resulting in excellent yields of

Post-Ugi gold-catalyzed diastereoselective domino cyclization for the synthesis of diversely substituted spiroindolines

• Amit Kumar,
• Dipak D. Vachhani,
• Sachin G. Modha,
• Sunil K. Sharma,
• Virinder S. Parmar and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2013, 9, 2097–2102, doi:10.3762/bjoc.9.246

• step is a cationic gold-catalyzed intramolecular hydroarylation tandem cyclization to produce spiroindolines with complete diastereoselectivity. This synthetic sequence is atom economic and mild conditions are applied to generate a very complex molecular structure from readily available starting

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• oxalyl chloride and the Lewis acid tin(IV) chloride, a tandem cyclization (Bischler–Napieralski/Friedel–Crafts acylation reaction) was triggered to directly give 137 and 149 [122][127]. In 2006, another approach to aristoyagonine (136) was reported by the group of Couture (Scheme 20) [128]. For the

One-pot tandem cyclization of enantiopure asymmetric cis-2,5-disubstituted pyrrolidines: Facile access to chiral 10-heteroazatriquinanes

• Ping-An Wang,
• Sheng-Yong Zhang and
• Henri B. Kagan

Beilstein J. Org. Chem. 2013, 9, 265–269, doi:10.3762/bjoc.9.32

• Moléculaire, Université Paris-Sud, 15 rue Georges Clemenceau, 91405 Orsay Cedex, France 10.3762/bjoc.9.32 Abstract A series of chiral 10-heteroazatriquinanes were synthesized from enantiopure asymmetric cis-2,5-disubstituted pyrrolidines through a one-pot tandem cyclization procedure. The structures and

• configurations of these new chiral 10-heteroazatriquinanes are confirmed by X-ray single-crystal diffraction analysis. Keywords: cis-2,5-disubstituted pyrrolidine; 10-heteroazatriquinane; tandem cyclization; X-ray single-crystal diffraction analysis; Introduction The azatriquinane derivatives are an important

• ][13][14] from compounds 4 through three steps, including reduction, debenzylation and cyclization (Scheme 1), but this failed. However, we have found a novel one-pot tandem cyclization of these enantiopure asymmetric cis-2,5-disubstituted pyrrolidines to produce chiral trisubstituted 10

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

Parallel and four-step synthesis of natural-product-inspired scaffolds through modular assembly and divergent cyclization

• Hiroki Oguri,
• Haruki Mizoguchi,
• Hideaki Oikawa,
• Aki Ishiyama,
• Masato Iwatsuki,
• Kazuhiko Otoguro and
• Satoshi Ōmura

Beilstein J. Org. Chem. 2012, 8, 930–940, doi:10.3762/bjoc.8.105

• diazotransfer, leading to cyclization precursors. The rhodium-catalyzed tandem cyclization and divergent cycloaddition gave rise to tetracyclic and hexacyclic scaffolds by the appropriate choice of dipolarophiles installed at modules 3 and 4. A different piperidine-based manifold 15 bearing an amino group was

• 3. Rhodium(II)-catalyzed tandem cyclization–cycloaddition [19][20][21] of the tetraketide-like precursors produced distinct multicyclic scaffolds, 4 and 5, differing in the relative orientations of the substructures. This approach illustrates a systematic way of diversifying skeletal arrays in a

• precursors 36–38 based on the unified three-step protocol. The Rh(II)-catalyzed tandem cyclization–cycloaddition of the branched precursors 36–38 exclusively occurred at module 3. The cyclized products 40–42, having the indole group at module 4 intact, were obtained in good yields. It is worth noting that

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• α-arylation product, followed by iminium formation in the presence of a secondary amine and subsequent tandem cyclization. The authors showed the importance of the ratio of the diverse reactants, notably that the amount of amine should remain low to avoid formation of aminal derivatives that would

Recent developments in gold-catalyzed cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2011, 7, 1075–1094, doi:10.3762/bjoc.7.124

• authors proposed that these intermediates formally behave as an all-carbon 1,4-dipole that intermolecularly reacts with the indole providing the final polycyclic furan adducts 9 in a regioselective fashion (Scheme 4) [46]. In 2009, J. Zhang reported a gold(I)-catalyzed tandem cyclization/(3 + 3

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• intramolecular hydroalkoxylation was reported by Zhang and co-workers [30]. A tandem cyclization mechanism was proposed by the authors. The first example of gold-catalyzed ring-opening addition of cyclopropenes has been developed by Lee’s group [31][32]. The reaction of alkyl-disubstituted cyclopropene 36 with a

• bond. Liu et al. has developed two highly stereoselective cationic gold(I)-catalyzed tandem cyclization reactions of alkynylindoles 322 [160]. The reaction proceeds with remarkable retention of chirality and allows the efficient enantioselective synthesis of polycyclic indolines 327 from the

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• protecting group at C9 which, upon liberation, would reveal the C9–C10 double bond found in mitomycin K. Applying the same radical process depicted in Scheme 27 with substrate 101, a tandem cyclization was observed to afford pentacycle 102. The basic pyrrolidine nitrogen was protected as its N-oxide and the