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

• the (S)-PyraBox–palladium complex. Examples of drugs containing a γ-lactam and derivative. Desymmetrization strategies employing Heck-Matsuda reactions. Heck–Matsuda reaction (1) and Jones oxidation (2) of the N-Boc-protected 2,5-dihydro-1H-pyrrole 1a. Reaction conditions: 1) pyrroline 1a (0.30 mmol

• –Matsuda reaction of the protected 2,5-dihydro-1H-pyrroles with aryldiazonium salts catalyzed by a (S)-PyraBox–palladium complex. Optimization of the reaction conditions with tosyl-protected pyrroline 1b.a Supporting Information Supporting Information File 4: Experimental procedures and characterization

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

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

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

• first step, vinyl triflate undergoes oxidative addition to give complex 4, which subsequently transmetalates with arylboronic acid to form palladium complex 5. In the case of Pd(PPh3)4, reductive elimination occurs to give enamide 2. However, using catalysts with very bulky ligands, such as Pd(dppf)Cl2

• causes the tautomerization of complex 5 [30] to zwitterionic carbene 6 which can now isomerize through the C–C bond rotation to the thermodynamically more stable palladium complex 7, followed by reductive elimination to enamide 3. A possible isomerization of enamides 2 or 3 in the presence of a catalyst

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• illustrated in Scheme 20 [105]. A methanofullerene variety 69 with a pincer ligand containing a disulfidoaryl moiety was synthesized from 3,5-bis(phenylsulfidomethyl)benzaldehyde hydrazone. In the presence of [Pd(CH3CN)4](BF4)2, the latter gives the corresponding palladium complex 70 (Scheme 21) [106]. A

Palladium-catalyzed regio- and stereoselective synthesis of aryl and 3-indolyl-substituted 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones

• Valeria Nori,
• Antonio Arcadi,
• Armando Carlone,
• Fabio Marinelli and
• Marco Chiarini

Beilstein J. Org. Chem. 2020, 16, 1084–1091, doi:10.3762/bjoc.16.95

• -alkynyltrifluoroacetanilides. In all these procedures, the activation of the triple bond was achieved by means of a σ-organyl palladium complex, in turn generated in situ by oxidative addition of a Pd(0) species to suitable organic electrophiles (aryl and vinyl halides or triflates [35][36], alkyl halides [37], alkynyl

Allylic cross-coupling using aromatic aldehydes as α-alkoxyalkyl anions

• Akihiro Yuasa,
• Kazunori Nagao and
• Hirohisa Ohmiya

Beilstein J. Org. Chem. 2020, 16, 185–189, doi:10.3762/bjoc.16.21

• -coupling, a stoichiometric experiment was conducted (Scheme 4). The reaction of the SIPr-ligated α-silyloxybenzylcopper 4 with the cinnamyl–palladium complex 5, which was prepared in situ from [(cinnamyl)PdCl]2 and DPPF, gave the corresponding homoallylic alcohol derivative 3aa. Based on previous reports

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

• fluorination of oxindoles with an axially chiral C2-symmetric N-heterocyclic carbene (NHC) palladium complex as a catalyst (Scheme 7a). The corresponding products were obtained in excellent yields but low to moderate enantioselectivities. Meanwhile, Wu and co-workers [42] developed a similar system using a

• BINAP-derived palladium complex to perform the similar reaction with 4,4’-diF-NFSI as the fluorinating agent in higher enantioselectivities (Scheme 7b). In 2012 the group of Sanford [43] achieved the palladium-catalyzed C–H fluorination of 8-methylquinoline derivatives using AgF as the nucleophilic

• (Scheme 10). Notably, this reaction used an air and moisture-stable chiral palladium complex as the catalyst, which worked well at low catalyst loading (as low as 0.5 mol %). In 2015, Shi et al. [47] introduced a Pd(II)/Pd(IV)-catalyzed fluorination of β-methylene C(sp3)–H bonds of α-amino acid

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

• experiments allowed the authors to propose the mechanism as follows (Scheme 20). First, cyclocondensation of 2-aminobenzamide (59) with 2-bromobenzaldehyde (62) to form intermediate 63 is followed by oxidative addition of Pd(0) to provide palladium complex 64. Then, insertion of CO (23) in the C–Pd bond

• , presumably by changing the anionic character of the palladium complex to cationic in intermediate 135. Finally, the Suzuki–Miyaura coupling of palladium salt 135 with boronic acid derivative 130 would provide the final oxindoles 131 or 132. Finally, is worth mentioning an example of a multicomponent

Chiral bisoxazoline ligands designed to stabilize bimetallic complexes

• Deepankar Das,
• Rudrajit Mal,
• Nisha Mittal,
• Zhengbo Zhu,
• Thomas J. Emge and
• Daniel Seidel

Beilstein J. Org. Chem. 2018, 14, 2002–2011, doi:10.3762/bjoc.14.175

• was reported to form a bis-palladium complex with one equivalent of [(η3-C3H3)PdCl]2 [51]. Little is known about the complexing abilities of compounds 9 and 11 [49][52]. The naphthyridine-based ligand 10 forms a dinuclear complex with nickel(ΙΙ) acetate (Ni∙∙∙Ni distance = 3.132 Å). Compound 12

Atom-economical group-transfer reactions with hypervalent iodine compounds

• Andreas Boelke,
• Peter Finkbeiner and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108

• copper species D to provide complex F. Isomerisation to the cis-palladium complex G and subsequent reductive elimination finally delivers 30. In such sequences, the iodane can also be prone to autooxidation processes, as demonstrated by Dauban and co-workers. Alkyl-substituted PIDA derivatives 20c are

Palladium-catalyzed Heck-type reaction of secondary trifluoromethylated alkyl bromides

• Tao Fan,
• Wei-Dong Meng and
• Xingang Zhang

Beilstein J. Org. Chem. 2017, 13, 2610–2616, doi:10.3762/bjoc.13.258

• begins with the reaction of [PdLn(0)] with secondary trifluoromethylated 2 via a SET pathway to generate alkyl radical B. B subsequently reacts with alkene to produce new radical species D, which then recombines with [LnPd(I)Br] C to give the key palladium-complex E. Finally, a β-hydride elimination

An efficient Pd–NHC catalyst system in situ generated from Na₂PdCl₄ and PEG-functionalized imidazolium salts for Mizoroki–Heck reactions in water

• Nan Sun,
• Meng Chen,
• Liqun Jin,
• Wei Zhao,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 1735–1744, doi:10.3762/bjoc.13.168

• the palladium complex in Mizoroki–Heck reactions. Furthermore, the TON of the coupling of 4-bromoacetophenone (1a) and styrene (2a) with Na2PdCl4/L1 as the catalyst was calculated to be 10,000, which is much higher than for previously reported catalytic systems under aqueous conditions. After

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• yields (Scheme 33). The reaction yield were lowered by adding a radical-trapping reagent, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), indicating that radical HO·, which was generated from TBHP, may participate in the oxidation of the palladium complex from Pd(II) to Pd(IV). In 2016, Guin and co-workers

• directing groups including azo, amide, anilide, carbamate and unsymmetrical urea, could also promote the ortho-hydroxylation of arenes. Remarkably, 1,4-dioxane not only served as the solvent, but also played an indispensable role in the oxidation of the palladium complex by generating hydroxyl radicals

Highly bulky and stable geometry-constrained iminopyridines: Synthesis, structure and application in Pd-catalyzed Suzuki coupling of aryl chlorides

• Yi Lai,
• Zhijian Zong,
• Yujie Tang,
• Weimin Mo,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen,
• Liqun Jin,
• Wen-hua Sun and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 213–221, doi:10.3762/bjoc.13.24

• under high temperature, if the palladium catalyst is stable enough. The formation of palladium black was observed in reactions of aryl chlorides using the reported palladium catalyst system, which inspired us to improve the thermal stability of the palladium complex. The steric environment adjacent to

A T-shape diphosphinoborane palladium(0) complex

• Patrick Steinhoff and
• Michael E. Tauchert

Beilstein J. Org. Chem. 2016, 12, 1573–1576, doi:10.3762/bjoc.12.152

• monometallic zerovalent palladium complex 9 featuring a distinct η1-B coordination mode, without the need of a stabilizing co-ligand. Findings For the synthesis of CyDPBPh we adapted the known reaction sequence for the production of Bourissou’s (o-PPh2-C6H4)2BPh ligand PhDPBPh (Scheme 1) [13][14]. Starting

• complex 9 the trans-coordinated palladium center featured an obtuse P1–Pd1–P2 angle of 157.72(2)°. Conclusion In conclusion we synthesized the zerovalent palladium complex [{(o-PCy2-C6H4)2BPh}Pd(0)] 9. Complex 9 supplements the few known examples (e.g., 6 [11]) of 14 VE palladium complexes bearing a

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

• Takashi Nishikata,
• Alexander R. Abela,
• Shenlin Huang and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

• complexes are commercially available, they may also be generated in situ via a variety of routes (Scheme 2), including: (a) reaction of a palladium complex with a non-coordinating anion source, usually an acid or metal salt; (b) reaction of Pd(II) halide complexes and silver salts [143][144][145]; (c

• likely initial intermediate associated with palladation and subsequent C–H bond cleavage. In order to confirm palladacycle formation in our reactions with arylureas, the dicationic palladium complex [Pd(MeCN)4](BF4)2 was exposed to one equivalent of 3-methoxyphenylurea 1f at room temperature for 20

• no stoichiometric quantities of competing acetate anions, additional acid is not needed to produce and maintain active catalyst. Proposed mechanisms Our results have demonstrated that a dicationic palladium complex effectively catalyzes C–H activation of arylureas at room temperature. Based on these

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• of the heterocycles. The addition of one equivalent of 7 to a methanolic solution of Na2PdCl4 gave the palladium complex 8 in 75% yield. The coordination sphere has two chlorine atoms bonding in a cis configuration to the Pd center and the oxazoline ligand chelating to the Pd center via the two

Weakly nucleophilic potassium aryltrifluoroborates in palladium-catalyzed Suzuki–Miyaura reactions: relative reactivity of K[4-RC₆F₄BF₃] and the role of silver-assistance in acceleration of transmetallation

• Vadim V. Bardin,
• Anton Yu. Shabalin and
• Nicolay Yu. Adonin

Beilstein J. Org. Chem. 2015, 11, 608–616, doi:10.3762/bjoc.11.68

• Ag2O and assumed the generation of a hydroxy–palladium complex with higher ability to transmetallation under the action of the corresponding organoboron reagent than ArPdL2X. For example, complex trans-C6F5Pd(PEt3)2OH is formed in the reaction of trans-C6F5Pd(PEt3)2I with Ag2O in toluene–water and

• ) in 92% yield. The latter is thermally stable and does not produce the cross-coupling product even upon heating in toluene at 100 °C for 24 h [21]. The authors suggested that acceleration of these reactions by silver(I) oxide results in the generation of a hydroxy–palladium complex with a higher

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

• considered in more detail in reviews on the palladium complex-catalyzed functionalization of allyl-containing compounds [20][21]. It is suggested that the reaction proceeds through the cleavage of the allylic C–H bond in 222 to form π-allyl–palladium complex 223 followed by the nucleophilic attack of acetate

• palladium-complex-catalyzed acetoxylation of terminal alkenes 226 under non-optimized conditions can afford a large number of products: vinyl acetate 227 and methyl ketone 228 (Wacker reaction), E and Z isomers of linear allyl ethers 229 and 230, and branched allyl ether 231 (Scheme 48) [218]. It was found

A novel 4-aminoantipyrine-Pd(II) complex catalyzes Suzuki–Miyaura cross-coupling reactions of aryl halides

• Claudia A. Contreras-Celedón,
• Darío Mendoza-Rayo,
• José A. Rincón-Medina and
• Luis Chacón-García

Beilstein J. Org. Chem. 2014, 10, 2821–2826, doi:10.3762/bjoc.10.299

• -bromobenzaldehyde (2e) were chosen as the model substrates, which in the coupling reaction produced the biphenyl 3q (see Table 2 and Table 3). We first describe the results of these screens. The screen for solvents was carried out using 0.3 mol % of the palladium complex as a catalyst and many bases; the results

Phosphinocyclodextrins as confining units for catalytic metal centres. Applications to carbon–carbon bond forming reactions

• Matthieu Jouffroy,
• Rafael Gramage-Doria,
• David Sémeril,
• Dominique Armspach,
• Dominique Matt,
• Werner Oberhauser and
• Loïc Toupet

Beilstein J. Org. Chem. 2014, 10, 2388–2405, doi:10.3762/bjoc.10.249

• analogue of 3 starting from [PdCl2(PhCN)2] failed, the corresponding reaction leading to a mixture of equilibrating species that could not be separated. However, when the reaction mixture was subjected to column chromatography on wet SiO2, a single aqua palladium complex (5) was recovered in high yield (90

• Table 3 and Table 4 correspond to the mean value from two catalytic tests. CD-based mono- and diphosphines with inward-pointing phosphorus atoms. X-ray structure of aqua palladium complex 5 [44] (top: side view; bottom: view from the primary face). The cavity contains two non-coordinated water molecules

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• transfer yields the phosphine product 51 [124][125]. A chiral Pincer-palladium complex 55 has been used for the addition of diarylphosphines 25c to enones 53 (Table 4) [126]. Several enones 53, having electron-donating or -withdrawing groups on the aromatic ring, reacted with a variety of electron-rich and

Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

• Phei Li Lau,
• Ray W. K. Allen and
• Peter Styring

Beilstein J. Org. Chem. 2013, 9, 2886–2897, doi:10.3762/bjoc.9.325

• and even “solventless” systems [9][10][11][12]. Pioneering work using SCFs as reaction media was carried out independently in the late 1990s [13][14] using a palladium complex with fluorinated phosphine ligands. Most of the published results utilising supercritical fluid media have been based on

Palladium(II)-catalyzed Heck reaction of aryl halides and arylboronic acids with olefins under mild conditions

• Tanveer Mahamadali Shaikh and
• Fung-E Hong

Beilstein J. Org. Chem. 2013, 9, 1578–1588, doi:10.3762/bjoc.9.180

• protocol has been developed employing an imidazole-based secondary phosphine oxide (SPO) ligated palladium complex (6) as a precatalyst. The catalytic coupling of aryl halides and olefins led to the formation of the corresponding coupled products in excellent yields. A variety of substrates, both electron

• of arylboronic acids with olefins, which were catalyzed by Pd(OAc)2 and employed N-bromosuccinimide as an additive under ambient conditions. The resulted biaryls have been obtained in moderate to good yields. Keywords: aryl halides; Heck reaction; olefins; palladium-complex; phosphine; Introduction

• ][29][30][31]. Previously, we also reported the synthesis of cobalt-containing SPO ligands and their palladium complex. This was successfully applied as a catalytic precursor in oxidative Heck reactions [32]. However, these reactions were carried out at high temperatures with limited substrate scope