Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

Cerium-photocatalyzed aerobic oxidation of benzylic alcohols to aldehydes and ketones

• Girish Suresh Yedase,
• Sumit Kumar,
• Jessica Stahl,
• Burkhard König and
• Veera Reddy Yatham

Beilstein J. Org. Chem. 2021, 17, 1727–1732, doi:10.3762/bjoc.17.121

• generating oxygen-centered radicals, that lead to carbon-centered radicals through intra/intermolecular hydrogen atom transfer (HAT) processes, radical decarboxylative or radical deformylation [57][58][59]. In continuation of our research interest on visible-light-driven cerium photocatalysis [59][65], we

Copper-mediated oxidative C−H/N−H activations with alkynes by removable hydrazides

• Feng Xiong,
• Bo Li,
• Chenrui Yang,
• Liang Zou,
• Wenbo Ma,
• Linghui Gu,
• Ruhuai Mei and
• Lutz Ackermann

Beilstein J. Org. Chem. 2021, 17, 1591–1599, doi:10.3762/bjoc.17.113

• also proved to be a viable substrate. Thus, the corresponding isoindolone 3aa was assembled via a tandem decarboxylative C−H/C−C sequence (Scheme 3a). The practical relevance of our approach was reflected by the cleavage of the N-2-pyridylhydrazide group, yielding S-3aa (Scheme 3b). Inspired by the

Heterogeneous photocatalytic cyanomethylarylation of alkenes with acetonitrile: synthesis of diverse nitrogenous heterocyclic compounds

• Guanglong Pan,
• Qian Yang,
• Wentao Wang,
• Yurong Tang and
• Yunfei Cai

Beilstein J. Org. Chem. 2021, 17, 1171–1180, doi:10.3762/bjoc.17.89

• conditions. Recently, we demonstrated K-modified carbon nitride (CN-K), a semiconductor material, exhibited a remarkably enhanced photocatalytic activity in the decarboxylative Giese reaction. The effect was due to its K-intercalated poly(heptazine)-based structure existing as small lamellar nanocrystallites

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• straightforward synthesis of the alkaloid (−)-pelletierine (112) was accomplished by the diastereoselectivity coupling of 3-oxobutanoic acid (110) and the N-tert-butanesulfinyl imine (RS)-109 derived from 5-bromopentanal (114). The base-promoted decarboxylative-Mannich coupling of these reagents led to β-amino

Selective synthesis of α-organylthio esters and α-organylthio ketones from β-keto esters and sodium S-organyl sulfurothioates under basic conditions

• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Thiago Barcellos,
• Claudio C. Silveira and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2021, 17, 234–244, doi:10.3762/bjoc.17.24

• -rich N-heterocycles [2][3][4], decarboxylative cross-coupling reactions with propiolic acid derivatives [5], Michael addition reaction [6], cross-couplings catalyzed by Pd [7] and Cu salts [8][9], the preparation of symmetrical and nonsymmetrical disulfides [10][11], and the synthesis of β-acetamido

Decarboxylative trifluoromethylthiolation of pyridylacetates

• Ryouta Kawanishi,
• Kosuke Nakada and
• Kazutaka Shibatomi

Beilstein J. Org. Chem. 2021, 17, 229–233, doi:10.3762/bjoc.17.23

• Ryouta Kawanishi Kosuke Nakada Kazutaka Shibatomi Department of Applied Chemistry and Life Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Japan 10.3762/bjoc.17.23 Abstract Decarboxylative trifluoromethylthiolation of lithium pyridylacetates was

• subsequent decarboxylative trifluoromethylthiolation were performed in a one-pot fashion. Keywords: decarboxylation; fluorinated compounds; pyridine compounds; trifluoromethylthiolation; Introduction The pyridine ring is found in numerous biologically active compounds. Therefore, efficient methods for

• recently attracted much attention [12][13][14][15]. Previously, our research group achieved decarboxylative functionalization of tertiary β-ketocarboxylic acids by exploiting their special ability to readily undergo decarboxylation [16][17][18][19][20][21]. During the course of this study, we found that

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

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• ][119][120][121][122]. There are many approaches to photosensitized fluorination that do not involve direct C–H activation, which are reviewed elsewhere [123][124][125], such as C–C bond fragmentation/C–F bond formation [126], aminofluorination of cyclopropanes [127] and decarboxylative fluorination

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

An overview on disulfide-catalyzed and -cocatalyzed photoreactions

• Yeersen Patehebieke

Beilstein J. Org. Chem. 2020, 16, 1418–1435, doi:10.3762/bjoc.16.118

• and abundant source of biomass-derived molecules. Decarboxylative transformations of carboxylic acids into value-added chemical products (such as biofuels) are a key objective in organic synthesis [25]. In 2014, Wallentin and co-workers reported a type of decarboxylation reaction of α-amino acids, α

Synthesis of pyrrolidinedione-fused hexahydropyrrolo[2,1-a]isoquinolines via three-component [3 + 2] cycloaddition followed by one-pot N-allylation and intramolecular Heck reactions

• Xiaoming Ma,
• Suzhi Meng,
• Xiaofeng Zhang,
• Qiang Zhang,
• Shenghu Yan,
• Yue Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2020, 16, 1225–1233, doi:10.3762/bjoc.16.106

• due to the low yield at the N-allylation step. Same result happened to 9o in which hindered iBu blocked the N-allylation. We next employed intermediated 6 prepared from the decarboxylative [3+2] cycloaddition of amino acids for one-pot N-allylation and intramolecular Heck reactions under the same

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

• . Other organic dyes, including several acridinium salts, have been successfully applied in organophotocatalytic decarboxylation protocols. For example, rhodamine 6G (OD14, E(PC+*/PC) ≈ 1.2 V) [42] was used for the photocatalytic decarboxylative azidation of cyclic amino acids and rose bengal (OD15) [43

• ] for a decarboxylative amination of indoline-2-carboxylic acids with azodicarboxylate esters. Another photocatalytic strategy for accessing C(sp3) radicals from carboxylic acids proceeds through a reductive decarboxylation pathway. This approach relies on the conversion of the acid into an easy

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

• the reaction conditions (see 4a, 4f, 5d and 5f), despite a successful report on their decarboxylative arylation under nickel-photoredox-catalyzed conditions [19]. As this report and MacMillan’s report use more basic, but less nucleophilic bases than DABCO, namely Barton’s base and MTBE, the issue

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• ). For an oxidative quenching, the photoarylation of heteroarenes and alkynes with aryldiazonium salts, and the oxidative decarboxylative coupling between cinnamic acid and tetrahydrofuran also showed better results when NiTPP was used instead of eosin [32][33][34] (Scheme 10). Regarding protocols

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

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

• -photocatalyzed intramolecular decarboxylative C–N coupling of NHP esters using an in situ-formed heteroleptic copper complex (Scheme 23) [38]. This protocol, a versatile alternative to the Curtius rearrangement, was applied to a large variety of substrates, including primary/secondary alkyl, cycloalkyl, and

• with the [Cu(II)] species bearing the phthalimide forms the product and regenerates the active [Cu(I)] catalyst. Collins and co-workers described the use of [Cu(I)(dq)(binap)]BF4 as an efficient catalyst for the reductive decarboxylative coupling of a NHP ester derived from cyclohexanecarboxylic acid

• with a bromoalkyne (Scheme 24) [39]. The catalyst was selected using a combinatorial approach for the selection of the optimal catalyst structure. The product was isolated in an excellent 87% yield. In 2018, Wang, Xu, and co-workers described the reductive decarboxylative alkylation of glycine and

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

• decarboxylative activation we anticipated its possibilities in cyclopropanation. The chloromethyl radical generation by photoredox catalysis is a useful strategy for cyclopropanation [58]. Most photoredox catalyzed, decarboxylative generations of carbon-centered radicals are based on the formation of “stabilized

Room-temperature Pd/Ag direct arylation enabled by a radical pathway

• Amy L. Mayhugh and
• Christine K. Luscombe

Beilstein J. Org. Chem. 2020, 16, 384–390, doi:10.3762/bjoc.16.36

• groups. 2-Substituted benzoic acids in general, and 2-nitrobenzoic acid in particular, are reactive substrates in decarboxylative coupling reactions [16][17]. However, more forceful conditions are typically required than used in the room-temperature system. Indeed, a very similar Pd/Ag system has been

• reported for decarboxylative coupling between indole and 2-nitrobenzoic acids at 110 °C [18]. Under such conditions, silver carboxylates decompose to produce carbonyl and phenyl radicals, which could explain the origin of nitrobenzene incorporation [19][20]. When the radical trapping agent BHT was added to

Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations

• Rafia Siddiqui and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26

• Figure 3, E0,0 is the energy gap between the ground state and the lowest triplet state, corresponding to the band gap in semiconductors. C–H acylation Decarboxylative acylation of acetanilides: In 2015, Wang and co-workers first reported the acylation of acetanilides via C–H functionalization using

• olefination. C–H olefination of phenolic ethers. Decarboxylative acylation of acetanilides. Synthesis of fluorenone derivatives by intramolecular deoxygenative acylation of biaryl carboxylic acids. Synthesis of benzothiazoles via aerobic C–H thiolation. Synthesis of benzothiazoles via oxidant-free C–H

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

• (III)–F species. Other catalysts Other transition metals, including Co, Ni, Fe, Ag, Ir, Mn, etc., have received more and more attention. Aliphatic and benzylic C–H fluorination and decarboxylative fluorination: In 2012, a silver-catalyzed radical decarboxylative fluorination of aliphatic carboxylic

• substrates with or without an electron-withdrawing group (EWG) in the presence of Selectfluor (Scheme 39). Notably, an EWG beta to the benzylic position is efficient for an excellent selectivity of the benzylic fluorination. Moreover, Gouverneur and co-workers [87] established the decarboxylative

• decarboxylative trifluoromethylation of various primary and secondary aliphatic carboxylic acids. With AgNO3 as a catalyst, (bpy)Cu(CF3)3 (bpy = 2,2’-bipyridine) as a CF3 source and K2S2O8 as an oxidant, aliphatic carboxylic acids were converted to the corresponding trifluoromethylated products in good yields

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

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

• undergoing two decarboxylation to give 5a. This type of thermal 1,3-oxygen-to-carbon rearrangement was already described by Trost in the early 80’s [48][49]. In view of the high temperature needed (130 °C for several hours or under microwave irradiation), this decarboxylative rearrangement appears to require

• -forming annulations with dimethyl 3-oxoglutarate (1a). C–C/C–O bond-forming annulations with various bis-nucleophiles. Decarboxylative rearrangement of 4a into 5a. Proposed mechanism for the Pd-catalyzed part of the [3 + 2] annulation reaction. Proposed mechanism for the temperature dependent cyclization

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• one (path A), decarboxylative coupling to form intermediates 14 and 15, followed by a cyclization take place, while in the second path (B), the first step seems to be the formation of amide 16. Indeed, another multicomponent approach to isoindolinones uses iodobenzamides 17 as starting materials

• = OH, conditions B, Scheme 9) instead of diketones and a quaternary ammonium salt as catalyst in water. In this multicomponent decarboxylative alkylation/cyclization process, they prepared several lactam derivatives 36 with good yields. While the first research group suggests that the reaction would