Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• acid (TFA) in CHCl3 for 3 hours at 65 °C under one-pot operation (Table 1, entries 1–6). Surprisingly, the reaction did not proceed when La(OTf)3 and ʟ-ascorbic acid were used as acidic catalysts (Table 1, entries 2 and 3). In contrast, the use of Brønsted acidic catalysts such as DBSA and PTSA

• -base porphyrins 9, 10 and 13 afforded zinc(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 14–16 in good yields (Scheme 1). The proposed mechanistic pathway for the formation of copper(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 3–8 under one-pot operation is presented in Figure 1. At the

An efficient metal-free and catalyst-free C–S/C–O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides

• Shubham Sharma,
• Dharmender Singh,
• Sunit Kumar,
• Vaishali,
• Rahul Jamra,
• Naveen Banyal,
• Deepika,
• Chandi C. Malakar and
• Virender Singh

Beilstein J. Org. Chem. 2023, 19, 231–244, doi:10.3762/bjoc.19.22

• -carbaldehyde 1, morpholine (C) and elemental sulfur under the standard reaction conditions as depicted in Scheme 5. It was noticed that this one-pot operation was completed within 2.5 hours and smoothly furnished the desired product, (5-(4-fluorophenyl)-1-phenyl-1H-pyrazol-3-yl)(morpholino)methanethione (1C

Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

• Sayan Pramanik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

• and operational simplicity through one pot reaction. Keywords: chemoselective conjugate reduction; dispirocyclopentanebisoxindole scaffolds; metal-free; one-pot operation; reductive cyclization; Introduction There is a vast demand of the structurally complex spirooxindole scaffold which is an

• generation of new cascade reactions to construct carbo- and heterocyclic moieties [27][28], we aimed to synthesize dispirocyclopentanebisoxindoles in one pot operation using a new protocol. Chemical hydrogenation of double bonded compounds like α,β-unsaturated ketones, approaching to saturated ketones, is an

• derivatives were synthesized on the basis of Michael acceptor ability of 3-alkylidene oxindoles with various donor synthons [16][17][18][19][20][21][22]. However, in spite of the progress in the synthesis of dispirocyclopentanebisoxindoles with concise structural and stereochemical diversity, the one-pot

New efficient synthesis of polysubstituted 3,4-dihydroquinazolines and 4H-3,1-benzothiazines through a Passerini/Staudinger/aza-Wittig/addition/nucleophilic substitution sequence

• Long Zhao,
• Mao-Lin Yang,
• Min Liu and
• Ming-Wu Ding

Beilstein J. Org. Chem. 2022, 18, 286–292, doi:10.3762/bjoc.18.32

• yields with the advantages of mild one-pot operation conditions and easily accessible starting materials containing various common substituents. Some bioactive 3,4-dihydroquinazolines and 4H-3,1-benzothiazines. Representative preperation of 3,4-dihydroquinazolines and 4H-3,1-benzothiazines. Preparation

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

• Yuki Yamamoto,
• Akihiro Tabuchi,
• Kazumi Hosono,
• Takanori Ochi,
• Kento Yamazaki,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 2906–2914, doi:10.3762/bjoc.17.198

• facilitate the industrial use of α-bromolactones as important intermediates. Keywords: α-bromolactone; metal-free; one-pot operation; tetraalkylammonium hydroxide; two-phase system; Introduction Lactones are important heterocycles in the organic chemistry, materials science, and medicinal chemistry fields

Rapid regio- and multi-coupling reactivity of 2,3-dibromobenzofurans with atom-economic triarylbismuths under palladium catalysis

• Maddali L. N. Rao,
• Jalindar B. Talode and
• Venneti N. Murty

Beilstein J. Org. Chem. 2016, 12, 2065–2076, doi:10.3762/bjoc.12.195

• performed in a stepwise manner (step 1 and step 2) in a one-pot operation without any intermediate isolation. These results are given in Table 6. To elaborate, firstly we carried out the preparation of 2-aryl-3-bromobenzofuran in step 1 and it was followed by a second arylation at the 3-position as part of

• couplings were conducted employing different triarylbismuth reagents. These tris-couplings afforded 2,3,5-triarylated benzofurans 5.1–5.4 in 62–79% yields (Table 7, entries 1–4). To note, all the three new aryl couplings were obtained in 4 h short duration of time in a one-pot operation and is synthetically

• -pot operation are on par with that obtained in Table 5. This reflects the efficient nature of our established pot-economic protocol employing different triarylbismuth reagents. In literature, bis-aryl couplings with arylboronic acids were reported with good reactivity under different heating

Synergistic chiral iminium and palladium catalysis: Highly regio- and enantioselective [3 + 2] annulation reaction of 2-vinylcyclopropanes with enals

• Haipan Zhu,
• Peile Du,
• Jianjun Li,
• Ziyang Liao,
• Guohua Liu,
• Hao Li and
• Wei Wang

Beilstein J. Org. Chem. 2016, 12, 1340–1347, doi:10.3762/bjoc.12.127

• catalytic regio- and enantioselective [3 + 2] annulation process, which offers a new approach to synthetically important heavily functionalized chiral cyclopentane structures 3, bearing at least 3 stereogenic centers in this one-pot operation [77][78]. To test the feasibility of the designed [3 + 2

Facile synthesis of 4H-chromene derivatives via base-mediated annulation of ortho-hydroxychalcones and 2-bromoallyl sulfones

• Srinivas Thadkapally,
• Athira C. Kunjachan and
• Rajeev S. Menon

Beilstein J. Org. Chem. 2016, 12, 16–21, doi:10.3762/bjoc.12.3

• 2a were combined into a one-pot operation (mediated by KOH in ethanol). A plausible mechanistic rationalization of the 4H-chromene formation is presented in Scheme 5. Cesium carbonate mediates the dehydrobromination of 2a to produce the allenyl sulfone 5 (see Scheme 1, path d). Additionally

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• (ROM)/ring-closing metathesis (RCM) in a one-pot operation to generate complex targets. RRM delivers complex frameworks that are difficult to assemble by conventional methods. The noteworthy point about this type of protocol is multi-bond formation and it is an atom economic process. In this review, we

Design and synthesis of fused polycycles via Diels–Alder reaction and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha and
• Ongolu Ravikumar

Beilstein J. Org. Chem. 2015, 11, 1259–1264, doi:10.3762/bjoc.11.140

• bond forming and bond breaking events take place in a one-pot operation [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Interestingly, the stereochemical information from the starting material is transferrred to the product. Moreover, RRM enables unprecedented and indirect

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• the presence of the Pd(OAc)2/PhI(OAc)2 system in a AcOH/Ac2O mixture affords products 103 (Scheme 22) [56]. The acylation of oxime 101 and the C–H acetoxylation of 102 are performed as a one-pot operation. In the acetoxylation of alkyl groups, the methyl group is more reactive than the methylene one

A modular phosphate tether-mediated divergent strategy to complex polyols

• Paul R. Hanson,
• Susanthi Jayasinghe,
• Soma Maitra,
• Cornelius N. Ndi and
• Rambabu Chegondi

Beilstein J. Org. Chem. 2014, 10, 2332–2337, doi:10.3762/bjoc.10.242

• triene 6, a one-pot RCM/CM/chemoselective H2 was performed to obtain the bicyclo[4.3.1]phosphate 9 in 40% yield over 3 reaction steps in a one-pot operation (72% avg/rxn). In this example, the RCM reaction was performed in dicholoroethane (DCE) at 70 °C for 2 h, since lower reactivity was observed in

• over three reaction steps in the one-pot, sequential operation (75% avg/rxn). Triene 6 was next subjected to RCM, followed by CM with homoallylic alcohol 4 and LiAlH4 reduction to furnish tetraol 20 in an overall 40% yield over three reaction steps in a one-pot operation (72% avg/rxn). Tetraols 19 and

Asymmetric Ugi 3CR on isatin-derived ketimine: synthesis of chiral 3,3-disubstituted 3-aminooxindole derivatives

• Giordano Lesma,
• Fiorella Meneghetti,
• Alessandro Sacchetti,
• Mattia Stucchi and
• Alessandra Silvani

Beilstein J. Org. Chem. 2014, 10, 1383–1389, doi:10.3762/bjoc.10.141

• diversity by a one-pot operation, we attempted to realize a four-component (4CR) version. An equimolar mixture of isatin and (S)-phenyl ethylamine was reacted with 2a (2 equiv) and 3a (2 equiv) in methanol in the presence of MgSO4 as a dehydrating agent to promote the formation of the ketimine

A catalyst-free multicomponent domino sequence for the diastereoselective synthesis of (E)-3-[2-arylcarbonyl-3-(arylamino)allyl]chromen-4-ones

• Pitchaimani Prasanna,
• Pethaiah Gunasekaran,
• Subbu Perumal and
• J. Carlos Menéndez

Beilstein J. Org. Chem. 2014, 10, 459–465, doi:10.3762/bjoc.10.43

• developed a facile three-component diastereoselective synthesis of novel (E)-3-[2-arylcarbonyl-3-(arylamino)allyl]-4H-chromen-4-ones containing chromone and β-enaminoketone structural fragments from simple, readily available starting materials in a one-pot operation and in good to excellent yields. This

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

• formed in a one-pot operation, minimizing the formation of waste and competitive reactions [1]. In line with this, remarkable new strategies have been developed based on palladium-mediated coupling process. The purpose of this review is to discuss recent achievements in the design of palladium-catalyzed

Cobalt(II) chloride catalyzed one-pot synthesis of α-aminonitriles

• Surya K. De

Beilstein J. Org. Chem. 2005, 1, No. 8, doi:10.1186/1860-5397-1-8

• catalytic amount of CoCl2 afforded the corresponding 2-(N-anilino)-2-phenylacetonitrile in 91% yield. Similarly, a variety of aldehydes were coupled with a wide range of amines and potassium cyanide in a one-pot operation in the presence of a catalytic amount of CoCl2 at room temperature to give the