Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• literature examples of nitrate oxidation of different transition metals, such as palladium. Control reactions further supported this proposal, including the inability of alternative Fe(III) salts (e.g., FeCl3) to form more than stoichiometric azide product in the absence of added nitrate. We believe this

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• development since the pioneering work by Ullmann [13] and Goldberg [14]. Despite the significant advances, the main limitations are the harsh reaction conditions such as high temperatures, pressure, and unsustainability which limits their scalability for industrial applications. Further, palladium-catalyzed

• strategies for C–N bond formation have been extensively explored by various research groups for the N-arylation of amines. Specifically, seminal contributions by Buchwald [15] and Hartwig [16] involving the use of palladium complexes as catalysts in the presence of either phosphine or diamine ligands for C–N

• bond formation. However, these methods suffer from limitations such as moisture sensitivity, the requirement of specific ligands, and the use of expensive palladium catalysts [17]. Also, Chan Lam, Evans, and other research groups have developed copper-catalyzed C–N bond formation reactions by careful

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• ]. Regioselective palladium-catalyzed prenylation of 2 with prenylboronic acid pinacol ester and subsequent hydrolysis with LiOH provided the linear prenylated acid 4 in good yield. Coupling acid 4 with N-hydroxyphthalimide using DCC and a catalytic amount of DMAP afforded the key intermediate 5 in 59% yield. With

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• direction, one potential strategy is the approach followed by Feringa and co-workers [72], in which palladium-porphyrin photosensitizer-based struts were employed within a metal-organic material, allowing the use of green light as irradiation source because of the effective energy transfer between these

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

• ). In 2015, a palladium-catalyzed cross dehydrogenative coupling of pyridine N-oxides with toluene for the regioselective arylation and benzylation of pyridine N-oxide was reported by Khan and co-workers [92] (Scheme 23). The authors have shown toluene 117 when used as benzyl and aryl source remained

• N-oxide 119b. In 2016, Wei and co-workers [93] reported the arylation of pyridine N-oxides 9 employing potassium (hetero)aryltrifluoroborates 126 as coupling partner using palladium acetate and TBAI (Scheme 24). Electron-withdrawing and donating groups on the pyridine N-oxide 9 resulted in the

• hydrolyzed to get the corresponding ketones. In 2018, Albéniz and group [99] reported the direct C3-arylation of pyridines with the help of bipy-6-OH as coordinating ligand under palladium catalysis (Scheme 29). In most of the cases the arylated pyridines 152 were obtained as mixtures of ortho-/meta-/para

Palladium-catalyzed enantioselective three-component synthesis of α-arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates

• Bastian Jakob,
• Nico Schneider,
• Luca Gengenbach and
• Georg Manolikakes

Beilstein J. Org. Chem. 2023, 19, 719–726, doi:10.3762/bjoc.19.52

• Bastian Jakob Nico Schneider Luca Gengenbach Georg Manolikakes Department of Chemistry, RPTU Kaiserslautern-Landau, Erwin-Schrödinger-Str. Geb. 54, D-67663 Kaiserslautern, Germany 10.3762/bjoc.19.52 Abstract A palladium-catalyzed enantioselective three-component reaction of glyoxylic acid

• products. Keywords: amino acids; asymmetric catalysis; multicomponent reaction; palladium catalysis; Petasis reaction; sulfonamides; Introduction α-Amino acids play a crucial role in every aspect of our human life [1]. They are important synthetic intermediates in the chemical industry and used for the

• palladium-catalyzed three-component reactions between arylboronic or carboxylic acids, amides or sulfonamides and different aldehyde components as attractive and broadly applicable alternative to the classical Petasis borono-Mannich reaction (Scheme 1b) [17][18][19][20][21]. Recently, we were able to extend

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• synthesised via a copper-catalysed Ullman-type coupling or a palladium-catalysed Buchwald–Hartwig amination (Scheme 9). Performing the rearrangement at high temperatures resulted in the undesirable formation of acridine byproducts 44. Cleaner reaction profiles could be obtained at a lower temperature (100 °C

• thioethers from aryl halides and triflates through palladium catalysis [50][51]. Scheme 10 provides a retrosynthesis of amination in the synthesis of dibenzo[b,f]azepine 45 as an example. Arnold et al. [30] reported an excellent method for the convergent synthesis of variable sized dibenzo-fused heterocycles

• precursor 102 and the complementary aldehyde 103. 3.4 Catellani-type reaction The Catellani reaction involves palladium-norbornene cooperative catalysis to functionalise the ortho- and ipso-positions of aryl halides by alkylation, arylation, amination, acylation, thiolation, etc. [63]. Della Ca' et al. [64

Synthesis of medium and large phostams, phostones, and phostines

• Jiaxi Xu

Beilstein J. Org. Chem. 2023, 19, 687–699, doi:10.3762/bjoc.19.50

• -methylphenyl)benzothiophene-fused 2-hydroxy-1-oxa-2-phosphacycloundecane 2-oxide 36 in 83% yield (Scheme 7) [22]. 1.1.2 Synthesis via other C–C bond formations: The palladium-catalyzed intramolecular Heck arylation of 2-bromophenylmethyl alk-1-enylphosphinates 37 provides access to 4-alkylidene-1,4

• palladium-catalyzed intramolecular arylation of 3-(2-bromophenyl)propyl alkylphosphinates 61 approached the synthesis of 3,4,5-trihydrobenzo[c][1,2]oxaphosphepine 1-oxides 62 in moderate 39–45% yields in the presence of triethylamine in dry toluene at 100 °C [33]. When the substrates were extended to 5

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

• sketched in red, with newly formed cyclic structures being highlighted. Review Earth-abundant metals Among the transition metal used in organic synthesis, the late transition metals like rhodium, palladium, and iridium have taken center stage when it comes to methodology development. Although these late

• ][19][20][21][22][23][24][25][26][27]. In this section, we summarize recent progress in Ni, Fe, Cu, and Co-catalyzed domino reactions of strained bicyclic alkenes. Nickel-catalyzed reactions Without close inspection, nickel might seem like the peculiar younger sibling of palladium within the field of

• transition-metal catalysis. Nickel lies directly above palladium in the periodic table, as such, it readily performs many of the same elementary reactions. Because of their reactive commonalties, nickel is often seen as the budget-friendly replacement; however, this misconception will clearly be refuted in

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• ; palladium; synthetic method; Introduction Nowadays, fluorinated molecules represent an indispensable class of molecules in chemistry and in chemical biology. Thanks to the unique properties of the fluorine atom or fluorinated groups to modulate biological and physicochemical properties of the parent non

• electron-withdrawing groups were functionalized and the expected products were isolated in moderate to high yields (4a–f, 58–91%). Palladium catalysis: Several works have been reported for the palladium-catalyzed trifluoromethylthiolation reaction of various aromatic compounds 5 by C–H bond activation and

• involved in most cases an electrophilic SCF3 source (R1R2NSCF3). For these transformations, the following working hypothesis was generally suggested (Scheme 4). After coordination of the palladium catalyst to a directing group, the metallacycle A is formed. This latter undergoes an oxidative addition in

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• Dihydrolevoglucosenone (DLG) is prepared by hydrogenation of levoglucosenone in the presence of palladium as a catalyst. Recently, Debsharma et al. reported the CROP of levoglucosenyl alkyl ether in CH2Cl2 at 0 °C and at room temperature using triflic acid or boron trifluoride etherate as initiators [46][47][48]. The 1H

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• reaction of 1 with bis(benzonitrile) palladium chloride generates the palladium chloride complex of 5 from which 5 can be liberated by treatment with dimethyl sulfoxide [43]. Compound 5, with tentatively assigned structure, was first obtained as a pyrolysis product of elemol phenylurethane (6) [44]. Its

Sequential hydrozirconation/Pd-catalyzed cross coupling of acyl chlorides towards conjugated (2E,4E)-dienones

• Benedikt Kolb,
• Daniela Silva dos Santos,
• Sanja Krause,
• Anna Zens and
• Sabine Laschat

Beilstein J. Org. Chem. 2023, 19, 176–185, doi:10.3762/bjoc.19.17

• ; hydrozirconation; palladium catalysis; Schwartz's reagent; terpenes; Introduction Conjugated dienones are recurring structural motifs in natural products. Several biologically relevant compounds carry (2Ε,4E)-unsaturated ketones or the corresponding esters or amides. Selected examples are clifednamide H (1) which

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

• Eric Gayon,
• Guillaume Lefèvre,
• Olivier Guerret,
• Adrien Tintar and
• Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

• to overall processes with a low atom economy, generating a significant amount of chemical waste, and which can be expensive when noble metals such as palladium salts are required (Scheme 1). The high efficiency of transition-metal-catalyzed cross-coupling methods in C–C bond formation processes

• constitutes an extremely powerful tool in total synthesis. In order to reach sustainable and economically appealing conditions, the quest for the substitution of palladium by non-noble metals has been investigated for more than four decades. To address this issue, new eco-friendly synthetic routes relying on

• cross coupling reaction developed by Kochi, leading to better yields, with no need to use an excess of one of the coupling partners (Scheme 2b) [12]. The yields obtained using this ligand-free method are comparable to those obtained in recent palladium-mediated alkyl–vinyl cross-couplings using

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• basic deprotection of the acetyl and benzoyl groups, followed by intramolecular cyclization and angelate esterification. Also, the differently redox-active DBCOD bearing an angelate functional group enabled the synthesis of kadsuphilin N (234). The synthetic sequence utilizes Fu’s protocol for palladium

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• continuous flow synthesis focus on palladium [85], cobalt [86], or copper (particularly useful for the widely used CuAAc) [87]. Nevertheless, the use of metal scavengers in large scale applications is limited as often discussed [88]. The use of a homogeneous scavenger as part of batch-based offline

Synthetic study toward the diterpenoid aberrarone

• Liang Shi,
• Zhiyu Gao,
• Yiqing Li,
• Yuanhao Dai,
• Yu Liu,
• Lili Shi and
• Hong-Dong Hao

Beilstein J. Org. Chem. 2022, 18, 1625–1628, doi:10.3762/bjoc.18.173

• was further confirmed through X-ray crystallographic analysis. With the key intermediate 10 in hand, we were in a position to test the planned two-step transformation including the palladium-catalyzed reductive cross coupling with HCO2H followed by Pd/C-catalyzed hydrogenation. To our surprise, the

A new route for the synthesis of 1-deazaguanine and 1-deazahypoxanthine

• Raphael Bereiter,
• Marco Oberlechner and
• Ronald Micura

Beilstein J. Org. Chem. 2022, 18, 1617–1624, doi:10.3762/bjoc.18.172

• -Deazaguanine (11) Compound 22 (111 mg, 462 µmol) and palladium on carbon 10% (Pd/C, 180.56 mg) were suspended in H2O/methanol 1:1 (7 mL). A rubber septum was applied and hydrogen gas (balloon with syringe) was bubbled through the solution for 10 minutes. The mixture was stirred under hydrogen atmosphere for

• )), 157.10 (H-C(6)); ESIMS (m/z): [M + H]+ calcd for 226.10; found, 226.10. 1-Deazahypoxanthine (30) Compound 31 (230 mg, 1.02 mmol) was dissolved in methanol (15 mL), then palladium on charcoal 10% (Pd/C, 400 mg, 337 µmol) was added and hydrogen (balloon with syringe and septum) was bubbled through the

Formal total synthesis of macarpine via a Au(I)-catalyzed 6-endo-dig cycloisomerization strategy

• Jiayue Fu,
• Bingbing Li,
• Zefang Zhou,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2022, 18, 1589–1595, doi:10.3762/bjoc.18.169

• building blocks 5 and 8 in hand, ketone 9 was prepared via a palladium-catalyzed Sonogashira coupling reaction in a yield of 95%. The precursor 10 for the gold(I)-catalyzed [19][20][21][22][23][24] cycloisomerization was then synthesized by treating ketone 9 with sodium bis(trimethylsilyl)amide (NaHMDS

Simple synthesis of multi-halogenated alkenes from 2-bromo-2-chloro-1,1,1-trifluoroethane (halothane)

• Yukiko Karuo,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2022, 18, 1567–1574, doi:10.3762/bjoc.18.167

• functionalized enyne structure that will be useful in various molecular transformations [27][28][29]. On the basis of a previous report, Sonogashira cross-coupling of 2 with trimethylsilylacetylene was performed with a bis(triphenylphosphine)palladium(II) dichloride. The reaction proceeded smoothly to give

• ), 153.9; 19F NMR (376 MHz, CDCl3) δ −80.5 (s, 1F), −80.6 (s, 1F); EIMS m/z: 250, 252 [M]+; HREIMS: [M]+ calcd for C8H5BrClFO, 249.9196, 251.9176; found, 249.9202, 251.9172. (3-Chloro-4-fluoro-4-phenoxybut-3-en-1-yn-1-yl)trimethylsilane (7): To a solution of 2a (0.5 mmol), bis(triphenylphosphine)palladium

An alternative C–P cross-coupling route for the synthesis of novel V-shaped aryldiphosphonic acids

• Stephen J. I. Shearan,
• Enrico Andreoli and
• Marco Taddei

Beilstein J. Org. Chem. 2022, 18, 1518–1523, doi:10.3762/bjoc.18.160

• ][25][26]. These catalytic cross-coupling reactions tend to follow similar pathways to the Michaelis–Arbuzov reaction, with the inclusion of a catalytic intermediate step. A number of suitable catalysts have been identified, ranging from nickel(II) bromide and nickel(II) chloride, to palladium(II

• ) acetate and palladium(II) chloride [23][27][28]. Reactions involving these catalysts are most often carried out at high temperatures, usually in excess of 160 °C, and involve slow dropwise addition of the trialkyl phosphite to the substrate [23]. In the search for milder reaction conditions, a new

• catalyst, tetrakis(triphenylphosphine)palladium(0), was introduced by Hirao and co-workers, which allowed for the lowering of the reaction temperature to approximately 90 °C [29][30][31]. In this work, we have developed an alternative experimental protocol to perform the Ni-catalyzed C–P cross-coupling

Design, synthesis, and evaluation of chiral thiophosphorus acids as organocatalysts

• Karen R. Winters and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2022, 18, 1471–1478, doi:10.3762/bjoc.18.154

• prepare chiral thiophosphorus acids have been described [41][42][43]. Once equipped with our new methods [38], the synthesis of indole-derived 2 was undertaken (Scheme 3). Known 3-allylindole (10) [44] was obtained from indole uneventfully. Intermediate 11 was furnished in moderate yield via our palladium

Dissecting Mechanochemistry III

• Lars Borchardt and
• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1454–1456, doi:10.3762/bjoc.18.150

• halides as substrates in multiple reactions. For instance, within this Thematic Issue, the synthetic relevance of aryl halides was evidenced during the development of a protocol for the solid-state palladium-catalyzed borylation reported by Kubota, Ito, and co-workers (Scheme 2) [6]. Moreover, Štrbac and

• . Mechanochemical palladium-catalyzed borylation protocol of aryl halides. 1,2-Debromination of polycyclic imides, followed by in situ trapping of the dienophile by several dienes. Synthesis of g-h-PCN from sodium phosphide and trichloroheptazine mediated by mechanochemistry. Mechanochemical intra- and

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

• Péter Kisszékelyi,
• Tibor Peňaška,
• Klára Stankovianska,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 1195–1202, doi:10.3762/bjoc.18.124

• isocyanoacetate (13). The palladium-catalyzed hydrogenation of intermediate 14 gave the racemic N-formyl-protected amino acid methyl ester 15 in good yield. Using either concentrated HCl (aq) or in situ-formed HCl from the reaction of MeOH and acetyl chloride, compound 15 could easily be deprotected to gain