Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• the presence of K2CO3 (3 equiv) as base, an isonitrile (1.2 equiv), and Pd(OAc)2 (10 mol %) which in situ undergoes a reduction to Pd(0) (Scheme 2). Another example was published by Wu's group, who carried out the synthesis of 1-(1H-indol-1-yl)-2-arylethan-1-one derivatives by promoting the formation

• of amides from 2-alkynylanilines by using TFBen (benzene-1,3,5-triyl triformate) as a CO source, Pd(OAc)2, DPEPhos (bis[(2-diphenylphosphino)phenyl] ether), and DIPEA (N,N-diisopropylethylamine) in MeCN. After 24 h, Pd(OAc)2 and AlCl3 were added to promote a selective cyclization reaction [14]. The

• selective cyclization to the indole derivative in the presence of Pd(OAc)2 and AlCl3. A variety of indole derivatives were synthetized in good isolated yields (Scheme 3). Synthesis of indoles by Pd(II)-catalyzed carbonylation reaction Oxidative carbonylation reactions, as well as all other types of

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

•  1). However, neither one of these new ligands performed better than L1 (see Table 1 below). In an attempt to enhance the protocol performance, we also evaluated the palladium source as indicated in Table 1. Switching Pd(TFA)2 by Pd(OAc)2 led to a minor increase in the yield, but without any changes

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• first examined by using 10 mol % Pd(OAc)2, 20 mol % PPh3, 2 equiv of Et3N in CH3CN or DMF at 105 °C for 24 h under N2 atmosphere. However, the reactions failed under these conditions (Table 1, entries 1 and 2). When K2CO3 was used as a base to replace Et3N, the reactions in either CH3CN or DMF for 3 h

• ., PCy3 and P(o-tol)3 reduced the yield of the desired product 6a (Table 1, entries 7 and 8). Lowering the amount of Pd(OAc)2 or changing the reaction temperatures resulted low yields of 6a (Table 1, entries 9–11). Similar results were observed from the reactions using other bases, such as K3PO4, NaOAc

• to use 1 mmol of 5a with 10 mol % Pd(OAc)2 and 20 mol % PPh3, 2 equiv of K2CO3 in 3 mL CH3CN at 105 °C for 3 h under N2 atmosphere which afforded product 6a in 70% yield (Table 1, entry 3). The combination of an initial multicomponent reaction with post-condensation reactions in one-pot is a good

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• , DMF/H2O, 60 °C, 18 h. (b) Pd(OAc)2, PPh3, CuI, phenylacetylene, Et3N, 50 °C, 5 h. (c) CuI, neocuproine, 4-MeOC6H4SH, NaOt-Bu, toluene, 110 °C, 13 h. (d) CuI, ʟ-proline, DMF, 80 °C, 14 h. (e) CuI, imidazole, Cs2CO3, DMF, 120 °C, 15 h. (f) 3-Methoxy-2-(trimethylsilyl)phenyl triflate, CsF, MeCN, rt, 18 h

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• started our studies with the palladium-catalyzed MCR of ethyl diazoacetate (1a), 1,3-butadiene (2a), and 1-phenylpiperazine (3a) in the presence of 5 mol % Pd(OAc)2 and 10 mol % Xantphos as ligand. To our delight, after irradiation with blue LED light in dimethylformamide (DMF) for 12 h at room

• strategy with diazo esters to access unsaturated γ- and ε-AA derivatives. Substrate scope of diazo compounds, 1,3-dienes and amines. aReactions (1/2/3/Pd(OAc)2/Xantphos = 0.3:0.4:0.2:0.01:0.02 mmol) were irradiated with blue LED light (467 nm) in 2.0 mL DMF at rt for 12 h under argon. Isolated yields

• . bAmine hydrochloride and Et3N (1.5 equiv) were used. cDiazo compound (0.4 mmol) was used. dPd(Ph3P)2Cl2 was used. For more experimental details, see Supporting Information File 1. Substrate scope of diazo compounds, allenes and amines. aReactions (1/5/3/Pd(OAc)2/Xantphos = 0.3.0.4:0.2:0.01:0.02 mmol

Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives

• Nahed Ketata,
• Linhao Liu,
• Ridha Ben Salem and
• Henri Doucet

Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37

• bases in the presence of Pd(OAc)2 as the catalyst (5 mol %) in DMA at 150 °C. This catalyst precursor is known to efficiently promote the direct coupling of 5-membered ring heteroarenes with aryl halides [25]. Cs2CO3 and K2CO3 proved to be totally inefficient bases, while acetate bases gave the desired

• ligands was examined. Slightly better yields of 1 were obtained using the diphosphine ligands dppe, dppb or dppf associated with Pd(OAc)2, and the preformed catalyst PdCl(C3H5)(dppb) gave 1 in 74% yield (Table 1, entries 7–10) [26]. The influence of a variety of solvents was also examined. DMF and NMP

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• out in the presence of o-phenylenediamine (1a) and 1,2-dibromobenzene (2) as model reactants using Pd(OAc)2 in combination with t-BuXPhos (2-di-tert-butylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl) (5 mol %), and Et3N (2.5 equiv) as base in DMF. In this case, DMF served as the CO surrogate, as it

• alternative palladium source, namely Pd2dba3, but again only traces of the compound 3a were observed (entry 6, Table 2). Next, we increased the Pd(OAc)2 catalyst loading to 10 mol % and the amount of the t-BuXphos ligand to 15 mol % in the presence of DBU and DMF. Under these conditions, the intermediate 3a

• DMF. The reaction was performed at 130 °C, as we believed that high temperature will promote the cyclization of the sterically hindered intermediate 3a, but no DBDAP was achieved under these conditions (entry 1, Table 3). Next, Pd(OAc)2 was employed under ligand-free conditions, but again the desired

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• of aryl sulfides by using the catalyst and the base. A catalytic cycle is shown in Scheme 4. Firstly, electrophilic Pd(TFA)2 generated from Pd(OAc)2 and TFA, which (by C–H functionalization of arene 4) led to intermediate II. Oxidative insertion of intermediate II into the N–S bond of 1 afforded

• sulfide moieties 11 was performed by Fu et al. (Scheme 6) [47]. Iron(III) chloride was used as a catalyst for this coupling reaction without the need of any ligand and additive. Screening for other metal salts, such as Cu(OAc)2, Pd(OAc)2, AgOAc or CuI was not successful, although FeS·7H2O, FeS, Fe2(SO4)3

• this work. In 2018, Anbarasan and Chaitanya developed an efficient approach for the C–H bond functionalization of aryl compounds containing a directing group using N-(thioaryl)phthalimides 14 in the presence of a palladium catalyst (Scheme 15) [53]. The thiolation occurred in the presence of Pd(OAc)2

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• -methylisochroman, 3-methoxyanisole). Mechanism experiments showed that the coupling of aromatic ring radicals with ether oxygen ions produced an intermediate radical cation, which achieves a catalytic cycle through the Cu center. Lee et al. disclosed TBHP as an oxidant and Pd(OAc)2/Cu(OTf)2 as the catalyst to

• achieve the CDC of THF and phenol C(sp2)–H (Scheme 12) [62]. The role of Pd may be through the formation of a Pd(II) phenolic acid salt from phenol and Pd(OAc)2 to improve the reactivity of phenol. Subsequently, a more complex C(sp2)–H component was employed as a coupling substrate to functionalize the

• tetrahydropyrans. CDC of thiazole with cyclic ethers. Cu(I)-catalyzed oxidative alkenylation of simple ethers. Cross-dehydrogenation coupling of isochroman C(sp3)–H bonds with anisole C(sp2)–H bonds. Pd(OAc)2/Cu(OTf)2-catalyzed arylation of α-C(sp3)–H bonds of ethers. Cu-catalyzed C(sp3)–H/C(sp2)–H activation

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• ), phenothiazine (130 mg, 0.650 mmol), Pd(OAc)2 (22 mg, 0.098 mmol), and sodium tert-butoxide (70 mg, 0.732 mmol) were dissolved in dry toluene (8 mL). Then, tri-tert-butylphosphine tetrafluoroborate (19 mg, 0.065 mmol) was added. The mixture was refluxed and stirred for 8 h under N2. After cooling, water (20 mL

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• styrenes (Scheme 14). Their preliminary investigation provided both C2 and C3-olefinated products, with the C2-selective product 69 as the major product (Scheme 14a). With the optimized conditions of Pd(OAc)2 (10 mol %), AgOAc (3 equiv), PivOH (2.5 equiv) in DMF, the method showed wide substrate scope and

• groups used Pd(OAc)2 as catalyst with 1,10-phenanthroline as ligand. The group of Yu used aryl halides 137 as coupling partner, whereas the group of Tan utilized aryl tosylates 142 as coupling partner (Scheme 26). The Yu group also applied the developed protocol for the synthesis of the drug molecule

Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions

• Masahiro Hosoya,
• Yusuke Saito and
• Yousuke Horiuchi

Beilstein J. Org. Chem. 2023, 19, 752–763, doi:10.3762/bjoc.19.55

• high potential for further optimization. Aerobic oxidation using transition metals instead of TEMPO was also investigated. Pd(OAc)2 (Table 1, entry 6) [42] and Cu(OAc)2 (Table 1, entry 7) [43], and Ni(OH)2 (Table 1, entry 8) [44] left the starting material 1a. Pd(OAc)2 led to moderate conversion, but

• Pd(OAc)2 did not dissolve in toluene even with pyridine. As a substitute for TEMPO, 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) was tried (Table 1, entries 9 and 10) [45]. Although the reactivity was improved compared with the TEMPO catalytic system in Table 1, entries 3–5, the DDQ catalytic system

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• (468.0 mg, 1.209 mmol), phenothiazine (289.0 mg, 1.452 mmol), Pd(OAc)2 (49.2 mg, 0.219 mmol) and sodium tert-butoxide (760.0 mg, 7.908 mmol) were dissolved in dry toluene (22 mL). Then tri-tert-butylphosphine tetrafluoroborate (66.4 mg, 0.229 mmol) was added. The mixture was refluxed and stirred for 8 h

• , 20.81, 10.66; HRMS–MALDI (m/z): [M + H]+ calcd for C32H30N2O3S, 522.1977; found, 523.2050. Synthesis of NI-PTZ2 Compound NI-PTZ2 was synthesized in a manner similar to [21]. Under N2 atmosphere, compound 1 (190.0 mg, 0.409 mmol), phenothiazine (294.5 mg, 1.478 mmol), Pd(OAc)2 (36 mg, 0.160 mmol), and

• a manner similar to [21]. Under N2 atmosphere, compound 2 (51 mg, 0.110 mmol), phenothiazine (26.3 mg, 0.132 mmol), Pd(OAc)2 (4.5 mg, 0.020 mmol), and sodium tert-butoxide (69.1 mg, 0.720 mmol) were dissolved in dry toluene (3 mL). Then, tri-tert-butylphosphine tetrafluoroborate (6.1 mg, 0.021 mmol

Palladium-catalyzed solid-state borylation of aryl halides using mechanochemistry

• Koji Kubota,
• Emiru Baba,
• Tamae Seo,
• Tatsuo Ishiyama and
• Hajime Ito

Beilstein J. Org. Chem. 2022, 18, 855–862, doi:10.3762/bjoc.18.86

• Discussion Initially, we conducted an optimization study on the mechanochemical cross-coupling between 2-bromo-6-methoxynaphthalene (1a, 0.3 mmol) and bis(pinacolato)diboron (2, 1.2 equiv) in the presence of Pd(OAc)2 (2 mol %), KOAc (3.0 equiv), and H2O (60 μL) as a liquid additive [43][44][45] (Table 1

• mixture of 1 (0.30 mmol), 2 (0.36 mmol), KOAc (0.9 mmol), Pd(OAc)2 (0.006 mmol), t-Bu3·HBF4 (0.009 mmol), and H2O (60 μL) was milled in a 1.5 mL stainless-steel jar at 30 Hz using one stainless-steel ball that was 5 mm in diameter. The isolated yields are shown. The NMR yields are shown in parentheses

• . Substrate scope of liquid aryl bromides. Reaction conditions: a mixture of 1 (0.30 mmol), 2 (0.36 mmol), KOAc (0.9 mmol), Pd(OAc)2 (0.006 mmol), t-Bu3·HBF4 (0.009 mmol), and H2O (60 μL) was milled in a 1.5 mL stainless-steel jar at 30 Hz using one stainless-steel ball that was 5 mm in diameter. The isolated

Mechanochemical halogenation of unsymmetrically substituted azobenzenes

• Dajana Barišić,
• Mario Pajić,
• Ivan Halasz,
• Darko Babić and
• Manda Ćurić

Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69

• protocol for the ortho-halogenation of acetanilide with NXS (X = Cl, Br, I) using Pd(OAc)2 as precatalyst in the presence of p-toluenesulfonic acid (TsOH) as an additive under solvent-free conditions [49]. Recently, Mal and Bera reported the utilization of NXS (X = Br, Cl) as bifunctional reagents for the

• azobenzene with NXS and Pd(OAc)2 as precatalyst in the presence of TsOH and MeCN as solid and liquid additives, respectively, led to the ortho-halogenated products relative to the azo group of the azobenzenes. In situ Raman monitoring of these reactions confirmed that the most favorable reaction pathway is

• electron-accepting substituents at the para position relative to the azo group: 4-chloroazobenzene (L6), 4-bromoazobenzene (L7), and 4-iodoazobenzene (L8) (Scheme 2 and Table 2). The synthetic protocols included milling the mixture of Ln/NXS/TsOH 1:1.2:0.5 equiv, 5 mol % Pd(OAc)2 precatalyst, and 15 µL

Regioselectivity of the S_EAr-based cyclizations and S_EAr-terminated annulations of 3,5-unsubstituted, 4-substituted indoles

• Jonali Das and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2022, 18, 293–302, doi:10.3762/bjoc.18.33

• indole derivative 31 in 82% yield (Scheme 11) [22]. Being a kinetically very active catalyst, Rh2(OAc)4 favored the formation of the five-membered ring. On the other hand, employment of Pd(OAc)2-catalysis switched the regioselectivity of this C–H insertion reaction. More specifically, under Pd(OAc)2

Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181

• contrast, only very few reports deal with the oxidative cyclization of nitrogen-containing biaryl intermediates. Ravi Kumar and Satyanarayana mentioned two successful control reactions using 2-phenylbenzylamine and 2-iminomethylbiphenyl with 5 mol % Pd(OAc)2 and 2 equivalents Ag2O in acetic acid at 140 °C

• aldehyde (33%) being generated (Table 2, entry 11). Similar results were obtained when adding iodine to promote benzylic oxidation [56] (Table 2, entry 12). Finally, Pd(OAc)2 was added in hopes of improving the mediation of C–C bond formation [38] (Table 2, entry 13). Interestingly, here the yield of

Ligand-dependent stereoselective Suzuki–Miyaura cross-coupling reactions of β-enamido triflates

• Tomáš Chvojka,
• Athanasios Markos,
• Svatava Voltrová,
• Radek Pohl and
• Petr Beier

Beilstein J. Org. Chem. 2021, 17, 2657–2662, doi:10.3762/bjoc.17.179

• product 3aa was preferentially formed (2aa/3aa, 29:71, Table 1, entry 6). Although other catalysts, such as Pd(acac)2, Pd(dba)2, and Pd(OAc)2(PPh3)2 showed good selectivity to inversion product 3aa, the products were formed in low yields (Table 1, entries 7–9). Further screening of the solvent and the

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• found with Pd(OAc)2/bpy as the catalyst, N-methylacetamide as the solvent, and a temperature of 80 °C. Variously substituted indoles as well as esters of 118 (R = aryl, alkyl, vinyl) were generally well tolerated, but oxa- (X = O) and azo- (X = NR) cyclobutanes met with limited success. Alternative

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• sterically hindered 1-(2-bromophenyl)-1,2,3-triazole derivatives 130. The target compounds, triazolo[1,5-a]indolones 131, were then obtained from 130 in high yield using catalytic amounts of Pd(OAc)2 and PCy3, carbon monoxide, and potassium carbonate and with heating in toluene at 120 °C. The structure of

• ) tetrafluoroborate (138) in the presence of HBF4 and NaNO2 at 0 °C. Next, the nanoparticles were obtained from the reduction of Pd(OAc)2 and Cu(OAc)2 employing NaBH4 in the presence of diazonium salt [63]. A possible mechanism for the synthesis of polycyclic triazoles 142 was proposed by Sekar et al. as well [63

• functionalized tricyclic triazoles 152–154. It was proved that o‐azidophenols 148 react well with alkynes 149 using CuI in DMF at 120 °C and then, the resulting intermediates react with isocyanides using Pd(OAc)2 and an O2 atmosphere at 120 °C to produce the desired products (Scheme 42). o‐Azidophenols 148 were

Recent advances in palladium-catalysed asymmetric 1,4–additions of arylboronic acids to conjugated enones and chromones

• Jan Bartáček,
• Jan Svoboda,
• Martin Kocúrik,
• Jaroslav Pochobradský,
• Alexander Čegan,
• Miloš Sedlák and
• Jiří Váňa

Beilstein J. Org. Chem. 2021, 17, 1048–1085, doi:10.3762/bjoc.17.84

• Minnaard group reported a protocol for the addition of boronic acids to enones [37]. At first, they tested the combination of Pd(OAc)2 with triflic acid (TfOH) to obtain a Pd(II) complex with a weakly coordinating anion that is necessary for a fast Pd–C bond cleavage and thus avoiding the undesired β

• underwent addition of phenylboronic acid (Scheme 4). The complex L2/Pd(OAc)2 was used to obtain the product with excellent enantioselectivity (95% ee) but only poor yield (12%) (Scheme 4) [38]. A catalytic system based on L2/Pd(OAc)2 was recently used by Khatua et al. for the synthesis of ar-macrocarpenes

• the reaction (Scheme 6) [40]. A different approach using microwave irradiation was explored by the group of Toma et al. [41]. After an initial tuning of the reaction conditions of a catalytic system based on Pd(OAc)2/2,2’-bipy several optically pure phosphoramidite and diphosphine ligands in

Total synthesis of pyrrolo[2,3-c]quinoline alkaloid: trigonoine B

• Takashi Nishiyama,
• Erina Hamada,
• Daishi Ishii,
• Yuuto Kihara,
• Nanase Choshi,
• Natsumi Nakanishi,
• Mari Murakami,
• Kimiko Taninaka,
• Noriyuki Hatae and
• Tominari Choshi

Beilstein J. Org. Chem. 2021, 17, 730–736, doi:10.3762/bjoc.17.62

• then examined the conditions reported by Orito and co-workers [30]. Gratifyingly, the treatment of 22c with Pd(OAc)2, Cu(OAc)2, and K2CO3 afforded the cyclized product 23 in 34% yield. The focus subsequently shifted to the total synthesis of trigonoine B (1) (Scheme 5). The key starting material, 2

• -iodo-5-methoxyaniline (24), was synthesized according to the procedure previously reported by Wetzel and co-workers [31]. The Suzuki–Miyaura coupling of 2-iodoaniline derivative 24 and pyrrole-3-boronic acid pinacol ester 13 was carried out in the presence of Pd(OAc)2 and SPhos, followed by the

• and desilylation, the electrocyclization of 29a proceeded smoothly to afford the desired 4-aminopyrroloquinoline 30a in 68% yield. Subsequently, the cycloamination of 30a in the presence of Pd(OAc)2, Cu(OAc)2, and K2CO3 gave tetrahydroquinoline 31 in 25% yield. However, although attempts were made to

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• . Previously, we have observed that the coupling system involving Xantphos/Pd(OAc)2 (used in the ratio of 15 mol %/15 mol % or 30 mol %/30 mol %) and t-BuOK or DIPEA in 1,4-dioxane as the solvent was effective for the C–N or C–S bond formation [30][31][35]. Unfortunately, it turned out, that the application of

• Xantphos/Pd(OAc)2/t-BuOK and our standard procedure [30][35], in which the amine is added after the lactam 3a, for the initial experiments ended with failure. In most cases, regardless of the used catalytic system (Pd source: Pd(OAc)2, Pd2(dba)3, ligand: DPEPhos, DavePhos, BINAP), solvent (1,4-dioxane

Total synthesis of decarboxyaltenusin

• Lucas Warmuth,
• Aaron Weiß,
• Marco Reinhardt,
• Anna Meschkov,
• Ute Schepers and
• Joachim Podlech

Beilstein J. Org. Chem. 2021, 17, 224–228, doi:10.3762/bjoc.17.22

• , K2CO3, DMF/acetone 1:2, 80 °C, 43 h (98%). Final steps in the synthesis of biaryl 1. Conditions: h) Pd(OAc)2, SPhos, Cs2CO3, dioxane/H2O 7:1, 70 °C, 18 h, (R = TBS: 98%, containing non-separable impurities; R = Bn: 89%) ; i) R = Bn: Pd/C (10%), H2, THF, 8 bar, 24 h, 40 °C (88%). NMR data of natural and

Novel library synthesis of 3,4-disubstituted pyridin-2(1H)-ones via cleavage of pyridine-2-oxy-7-azabenzotriazole ethers under ionic hydrogenation conditions at room temperature

• Romain Pierre,
• Anne Brethon,
• Sylvain A. Jacques,
• Aurélie Blond,
• Sandrine Chambon,
• Sandrine Talano,
• Catherine Raffin,
• Branislav Musicki,
• Claire Bouix-Peter,
• Loic Tomas,
• Gilles Ouvry,
• Rémy Morgentin,
• Laurent F. Hennequin and
• Craig S. Harris

Beilstein J. Org. Chem. 2021, 17, 156–165, doi:10.3762/bjoc.17.16

• ), DIPEA, DMF, 60 °C, 16 h, 44–71% 32a–h); d) TFA, rt, 30 min. for Boc protected amines (32b,c); e) Pd(OAc)2, TES, DCM/MeOH, rt, 16 h for Cbz protected amines. Selected results from conditions’ screening for pyridin-2-(1H)-one formation (7). Validation of library conditions.a Selected results from