Phosphinate-containing heterocycles: A mini-review

• Olivier Berger and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2014, 10, 732–740, doi:10.3762/bjoc.10.67

• have synthesized a few phosphindoles. The first phosphindole 6 was simply obtained in 84% yield by reacting an α,ω-bisphosphonate derivative 5 with n-butyllithium in a phospha-Dieckmann condensation (Scheme 3) [17]. Cyclohexyl 2-(biphenyl)-H-phosphinate 7 was cyclized using 2 mol % of Pd(OAc)2 in

Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions

• Andrea Caporale,
• Stefano Tartaggia,
• Andrea Castellin and
• Ottorino De Lucchi

Beilstein J. Org. Chem. 2014, 10, 384–393, doi:10.3762/bjoc.10.36

• -36075 Vicenza, Italy 10.3762/bjoc.10.36 Abstract Two efficient protocols for the palladium-catalyzed synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides in the absence of copper were developed. A simple catalytic system consisting of Pd(OAc)2 and P(p-tol)3 using DBU as the base and THF as the

• -pentynoic acid with aryl bromides, using a catalyst containing Pd(OAc)2 in combination with SPhos or XPhos in the presence of tetra-n-butylammonium fluoride (TBAF) as the base and THF as the solvent. Therefore, new efficient approaches to the synthesis of terminal acetylenes from widely available aryl

• in piperidine as the solvent [39][78] or by using aminophosphines [18] as well as phenanthryl imidazolium carbenes as the catalyst ligands [79]. A more practical methodology has been reported by Shirakawa in which a Pd(OAc)2/PPh3 catalyst system in DMSO and in the presence of K3PO4 as the base was

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

• . However, Pd/C freshly prepared from Pd(OAc)2 and activated charcoal according to Felpin [77] delivered consistent results (reaction time < 3 h). Although the Cbz-cleavage beside a benzyl moiety in alcohols as solvent is known (for selected examples of the chemoselective Cbz-cleavage of Bn, Cbz-protected

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

• Ludovic Eberlin,
• Fabien Tripoteau,
• François Carreaux,
• Andrew Whiting and
• Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

• -coupled using palladium catalysis. A one-pot sequence was also developed, first heating the boron diene with the dienophile, then adding an aryl halide, Pd(OAc)2 (5 mol %), K2CO3 (3 equiv) and finally refluxing the mixture in EtOH or MeOH for 5 h (Scheme 13). Reactions with various aryl halides

Diversity-oriented synthesis of dihydrobenzoxazepinones by coupling the Ugi multicomponent reaction with a Mitsunobu cyclization

• Lisa Moni,
• Luca Banfi,
• Andrea Basso,
• Alice Brambilla and
• Renata Riva

Beilstein J. Org. Chem. 2014, 10, 209–212, doi:10.3762/bjoc.10.16

• polarity of 10) to give the pure final product. Synthesis of benzyl azides. a) BnBr, K2CO3, acetone or DMF, rt or 60 °C (for 2d); b) 1) MsCl, Et3N, CH2Cl2, −10 °C; 2) NaN3, DMF, rt; c) NaBH4, MeOH, rt; d) PhB(OH)2, Cs2CO3, Pd(OAc)2, PPh3, 80 °C, 4.5 h; e) 1) MeOH, H2SO4, reflux; 2) LiAlH4, THF, rt

Synthesis of the B-seco limonoid core scaffold

• Hanna Bruss,
• Hannah Schuster,
• Rémi Martinez,
• Markus Kaiser,
• Andrey P. Antonchick and
• Herbert Waldmann

Beilstein J. Org. Chem. 2014, 10, 194–208, doi:10.3762/bjoc.10.15

• (OAc)2, DMSO, O2, overnight, 72% (3 steps); j) LDA, 1H-benzotriazole-1-methanol, THF, −78 °C, 3 h, 67%, de = 100%; k) TBSCl, imidazole, DMF, rt, overnight, 90%; l) H2O2, NaOH, MeOH, 0 °C, 1 h, 80%, de = 100%; m) NaBH4, (PhSe)2, EtOH, 0 °C to rt, 10 min, 93%; n) TESCl, imidazole, DMF, 40 °C, 2 h, 99%; o

• , 1.5 h, quant.; c) O3, CH2Cl2, −78 °C, then DMS, −78 °C to rt; d) TMSCHN2, CH2Cl2/MeOH (1:1), rt, 0.5 h, 59% (2 steps); e) NaBH4, MeOH, 0 °C, 0.5 h; f) TBDPSCl, imidazole, DMAP, CH2Cl2, 0.5 h, rt, 78% (2 steps); g) CH2Cl2/H2O/HClO4 (25:5:1), rt, 6 h; h) LiHMDS, TMSCl, THF, −78 °C to rt, 1.5 h; i) Pd

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• coworkers reported on the first Pd-catalyzed trifluoromethylation at C–H positions in aromatic compounds (Table 5) [67]. Pd(OAc)2 (10 mol %) was used as the catalyst, and Umemoto’s sulfonium tetrafluoroborate salt as the CF3 source rather than its triflate analogue. Trifluoroacetic acid and copper(II

• . However, it necessitates higher catalyst loadings (20 mol % CuCl vs 10 mol % Pd(OAc)2) to ensure acceptable yields. Various N-aryl and N-hetarylpivalamides were successfully converted under a nitrogen atmosphere, with introduction of the CF3 group predominantly ortho to the amide function (Table 17

Consecutive cross-coupling reactions of 2,2-difluoro-1-iodoethenyl tosylate with boronic acids: efficient synthesis of 1,1-diaryl-2,2-difluoroethenes

• Ju Hee Kim,
• Su Jeong Choi and
• In Howa Jeong

Beilstein J. Org. Chem. 2013, 9, 2470–2475, doi:10.3762/bjoc.9.286

• the presence of catalytic amounts of Pd(OAc)2 and Na2CO3 afforded the mono-coupled products 3 and 5 in high yields. The use of 4 equiv of boronic acids in the presence of catalytic amount of Pd(PPh3)2Cl2 and Na2CO3 in this reaction resulted in the formation of symmetrical di-coupled products 4 in high

• yields. Unsymmetrical di-coupled products 4 were obtained in high yields from the reactions of 3 with 2 equiv of boronic acids in the presence of catalytic amounts of Pd(OAc)2 and Na2CO3. Keywords: boronic acids; cross-coupling reaction; 1,1-diaryl-2,2-difluoroethene; 1,1-difluoro-1,3-dienes; 2,2

• . Since the use of a proper base in the Suzuki–Miyaura reaction is an important factor to increase the yield of coupled product, we screened bases to get the optimized reaction conditions. When 2 was reacted with 1 equiv of phenylboronic acid in the presence of 5 mol % of Pd(OAc)2 and Cs2CO3 (2 equiv) in

An easy direct arylation of 5-pyrazolones

• Hao Gong,
• Yiwen Yang,
• Zechao Wang and
• Chunxiang Kuang

Beilstein J. Org. Chem. 2013, 9, 2033–2039, doi:10.3762/bjoc.9.240

• ; C–H bond activation; Pd(OAc)2; pyrazolone; Introduction 5-Pyrazolones are attracting considerable research interest because of their unique chemical properties and their structures that facilitate their application as biological and pharmaceutical intermediates and products [1][2][3]. Over the

• commenced this study by performing the direct arylation of phenazone (1a) in the presence of 2 equiv of iodobenzene (2a), 10 mol % of Pd(OAc)2 as a catalyst in acetonitrile in a sealed tube. The results are shown in Table 1. Gratifyingly, a 45% yield of the desired product 3a was achieved after stirring for

• decreased to 42% (Table 1, entry 7). Reducing the dosage of Pd(OAc)2 to 0.05 equiv and 0.02 equiv, respectively, decreased the yield to 40% and 32% (Table 1, entries 8–9). Several solvents were examined under the conditions of entry 1. When the solvent was changed to THF, DCE, dioxane, and benzene, the

Enantioselective synthesis of planar chiral ferrocenes via palladium-catalyzed annulation with diarylethynes

• Yan-Chao Shi,
• Rong-Fei Yang,
• De-Wei Gao and
• Shu-Li You

Beilstein J. Org. Chem. 2013, 9, 1891–1896, doi:10.3762/bjoc.9.222

• the study by testing the reaction of ferrrocene 1a in a palladium-catalyzed direct coupling with diphenylethyne in the presence of 10 mol % Pd(OAc)2, 20 mol % Boc-L-Phe-OH, 25 mol % TBAB, and 100 mol % K2CO3 in DMA at 110 °C under air. To our great delight, the reaction furnished the desired product

• used instead of TBAB as the additive, excellent enantioselectivity was maintained. The enantioselectivity decreased dramatically when no additive was used (entry 16, Table 1). The optimized conditions were obtained as the following: 10 mol % Pd(OAc)2, 2.3 equiv of diarylethyne, 20 mol % Boc-L-Val-OH

• mg, 0.04 mmol), Pd(OAc)2 (4.5 mg, 0.02 mmol), K2CO3 (27.6 mg, 0.2 mmol), TBAB (tetrabutyl ammonium bromide) (16.1 mg, 0.05 mmol) and ferrocene 1 (0.02 mmol) successively. The mixture was stirred at 80 °C under air (open flask) for 48 h. After the reaction was complete, it was quenched with saturated

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

• 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

• catalyzed cross-coupling of aryl halides 1 with olefins 2 at 60 °C; and (ii) Pd(OAc)2 catalyzed arylation of arylboronic acids 4 with olefins at 25 °C (Scheme 1). Results and Discussion Heck reaction of aryl halides with olefins In the presence of solvents, secondary phosphine oxide (RR'P(O)H) might undergo

• optimized reaction conditions, phenylboronic acid (4a) and styrene (2a) were chosen as the model substrates and Pd(OAc)2 was employed as the catalyst. Various reaction conditions were tested and the results are presented in Table 3. Initially, a Pd(OAc)2 catalyzed Heck reaction was performed employing polar

Isolation and X-ray characterization of palladium–N complexes in the guanylation of aromatic amines. Mechanistic implications

• Abdessamad Grirrane,
• Hermenegildo Garcia and
• Eleuterio Álvarez

Beilstein J. Org. Chem. 2013, 9, 1455–1462, doi:10.3762/bjoc.9.165

• catalyzed by palladium salts [19], such as PdCl2 or Pd(OAc)2 in homogenous phase. Also recently we have reported that palladium nanoparticles supported on magnesia can be a solid catalyst for this process [20]. Working with PdCl2(NCCH3)2 in dichloromethane we were able to isolate two types of palladium

Practical synthesis of indoles and benzofurans in water using a heterogeneous bimetallic catalyst

• Cybille Rossy,
• Eric Fouquet and
• François-Xavier Felpin

Beilstein J. Org. Chem. 2013, 9, 1426–1431, doi:10.3762/bjoc.9.160

• , activated-charcoal-supported palladium catalyst for hydrogenation and debenzylation [33]. This homemade Pd/C catalyst was prepared by impregnation of activated charcoal by the reduction of Pd(OAc)2 in MeOH under an atmosphere of H2 (1 atm). With these previous results in mind, we reasoned that the

• concomitant impregnation of charcoal with palladium and copper could lead to a heterogeneous bimetallic catalyst, hopefully active for cascade Sonogashira alkynylation–cyclization sequences. Following this aim, we were pleased to find that the stirring of a mixture of Pd(OAc)2, Cu(OAc)2 and activated charcoal

• base. Current studies focusing on the preparation of more robust and recyclable heterogeneous bimetallic catalysts for batch and flow processes are underway in our laboratory. Experimental Catalyst preparation: The Pd–Cu/C was prepared by the following procedure. Pd(OAc)2 (119 mg, 0.5 mmol), Cu(OAc)2

Palladium-catalyzed synthesis of N-arylated carbazoles using anilines and cyclic diaryliodonium salts

• Stefan Riedmüller and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2013, 9, 1202–1209, doi:10.3762/bjoc.9.136

• The direct synthesis of N-arylated carbazoles through a palladium-catalyzed amination of cyclic iodonium salts with anilines is described. In particular, electron-poor aniline derivatives reacted smoothly with only 5 mol % of Pd(OAc)2 as catalyst to give the desired products in up to 71% yield

• equal or better in efficiency and yield. Changing Pd2(dba)3 to Pd(OAc)2 had no significant impact on product yields (Table 1, entry 12). Further increase of the catalyst ratio from 5 to 10 mol % had little effect (Table 1, entry 15). Next, we decided to analyze the byproducts of this reaction by GC–MS

• diaryliodonium salts by a ring opening/Buchwald-amination cascade using anilines and aliphatic amines as nitrogen-containing substrates. With 5 mol % of Pd(OAc)2 the desired N-arylcarbazoles could be isolated in up to 71% yield. Finally, the corresponding cyclic diarylbromonium derivatives were tested in the

Synthesis of phenanthridines via palladium-catalyzed picolinamide-directed sequential C–H functionalization

• Ryan Pearson,
• Shuyu Zhang,
• Gang He,
• Nicola Edwards and
• Gong Chen

Beilstein J. Org. Chem. 2013, 9, 891–899, doi:10.3762/bjoc.9.102

• States of America 10.3762/bjoc.9.102 Abstract We report a new synthesis of phenanthridines based on palladium-catalyzed picolinamide-directed sequential C–H functionalization reactions starting from readily available benzylamine and aryl iodide precursors. Under the catalysis of Pd(OAc)2, the ortho-C–H

• [26]. In 2012, our laboratory [28] as well as that of Daugulis [27] independently reported that picolinamide substrates can undergo intramolecular dehydrogenative C–H amination reactions to afford medium-sized N-heterocycles under the catalysis of Pd(OAc)2 with PhI(OAc)2 oxidant. These discoveries led

• . We commenced the study by investigating the arylation of 2-methoxybenzyl picolinamide 1 with 4-iodoanisole (2) under various conditions (Table 1) to form our desired arylated product 3. Our initial attempt under the original Pd(OAc)2-catalyzed AgOAc-promoted solvent-free condition afforded the

Intramolecular carbonickelation of alkenes

• Rudy Lhermet,
• Muriel Durandetti and
• Jacques Maddaluno

Beilstein J. Org. Chem. 2013, 9, 710–716, doi:10.3762/bjoc.9.81

• mixture of the three regioisomers 14–16 was recovered (Scheme 6). By contrast, under Larock’s conditions [33] [Pd(OAc)2 (5 mol %), Na2CO3, DMF, 80 °C], an even higher yield (90% after 2 days) was returned but consisted of a 1:1:1 mixture of the same three products 14–16. Replacing sodium carbonate by

Synthesis and structure of trans-bis(1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene)palladium(II) dichloride and diacetate. Suzuki–Miyaura coupling of polybromoarenes with high catalytic turnover efficiencies

• Jeelani Basha Shaik,
• Venkatachalam Ramkumar,
• Babu Varghese and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2013, 9, 698–704, doi:10.3762/bjoc.9.79

• -dimesityl-3-methyl-1,2,3-triazolium iodide with freshly prepared silver oxide followed by transmetalation with Pd(Cl)2(CH3CN)2 yielded 1 as a pale yellow solid in 87% (Scheme 1). The acetate complex 2 was prepared by the transmetalation of the silver carbene complex with Pd(OAc)2. Addition of Pd(OAc)2 to in

• generated as described above was subsequently treated with Pd(OAc)2 (75 mg, 0.34 mmol, 0.6 equiv) and stirred for 8 h. The reaction mixture was passed through a bed of celite, and then dichloromethane was removed under vacuum to give complex 2 as a pale yellow solid (430 mg, 0.5 mmol) in 89%.Crystals of 2

N-Heterocyclic carbene–palladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides

• Ismail Özdemir,
• Nevin Gürbüz,
• Nazan Kaloğlu,
• Öznur Doğan,
• Murat Kaloğlu,
• Christian Bruneau and
• Henri Doucet

Beilstein J. Org. Chem. 2013, 9, 303–312, doi:10.3762/bjoc.9.35

• variety of aryl chlorides using 5 mol % of Pd(OAc)2 associated to 10 mol % of Cy2P-o-biphenyl as the catalyst [26]. However, in most cases, such couplings were performed with aryl bromides or iodides [28][29][30][31][32][33][34][35][36][37][38][39]. The influence of mono- or diphosphines as ligands for

• , benzothiophene [42][45] or arenes [40]. Therefore, we employed carbenes bearing relatively bulky N-substituents. The reaction of Pd(OAc)2 with the corresponding benzimidazolium halides in DMSO at 60–110 °C gave 1–9 in 53–87% yields (Scheme 1). The geometry of these complexes was not defined, as no crystals

• 89% could be obtained in the presence of only 0.5 mol % of a triphosphine associated to Pd(OAc)2 as the catalyst [27]. With complexes 2, 3, 8 and 9, a high conversion of 4-chlorobenzonitrile (11) and good yields of the coupling product 16 were obtained (Table 1, entries 1–9). Then, in order to

Glycosylation efficiencies on different solid supports using a hydrogenolysis-labile linker

• Mayeul Collot,
• Steffen Eller,
• Markus Weishaupt and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 97–105, doi:10.3762/bjoc.9.13

• 2 steps; (f) TFA, DCM, rt, 99%; (g) NHS, DCC, DMAP, CH3CN, DCM, rt, 63%; (h) 2 M aq NaOH, THF, 55 °C, 92%; (i) p-TsOH·H2O, MeOH, DCM, rt, 94%; (j) Pd(OAc)2, HCOONH4, MeOH, H2O, 90%. Coupling of linker 1 to different resins. Reactions and conditions: (a) 1. 1 and 16 or 17, Cs2CO3, DMF, TBAI, 60 °C; 2

• ; 5. p-TsOH·H2O, MeOH, DCM, rt. Model glycosylation by using an automated oligosaccharide synthesizer. Reactions and conditions: (a) 34, TMSOTf, DCM, −15 °C (30 min); (b) 35, NIS, TfOH, DCM, dioxane, different temperatures and reaction times; (c) Pd(OAc)2, HCOONH4, H2O; (d) NaOMe, MeOH, DCM, rt

Highly stereocontrolled synthesis of trans-enediynes via carbocupration of fluoroalkylated diynes

• Tsutomu Konno,
• Misato Kishi and
• Takashi Ishihara

Beilstein J. Org. Chem. 2012, 8, 2207–2213, doi:10.3762/bjoc.8.249

• [15][16][17][18][19][20][21][22]. Thus, treatment of 2,3,3,3-tetrafluoro-1-iodo-1-propene (1), which could be easily prepared from 2,2,3,3,3-pentafluoropropanol in three steps [23], with 1.2 equiv of terminal alkynes 2 and 1.5 equiv of Et3N in the presence of 5 mol % of Pd(OAc)2 and 10 mol % each of

Palladium-catalyzed C–N and C–O bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols

• Rajendra Surasani,
• Dipak Kalita,
• A. V. Dhanunjaya Rao and
• K. B. Chandrasekhar

Beilstein J. Org. Chem. 2012, 8, 2004–2018, doi:10.3762/bjoc.8.227

• amides, amines and amino acid esters takes place rapidly by using the combination of Xantphos, Cs2CO3, dioxane and palladium catalyst precursors Pd(OAc)2/Pd2(dba)3. The combination of Pd(OAc)2, Xantphos, K2CO3 and dioxane was found to be crucial for the C–O cross-coupling reaction. This is the first

• Pd(OAc)2, Xantphos (L1) as a ligand [51][52][53], Cs2CO3 as a base and dioxane as a solvent provided the most successful result (Table 1, entry 1). The reaction temperature was maintained at ~100 °C in all cases. Switching the Pd source to Pd2(dba)3 resulted in a slight decrease in yield (Table 1

• , entry 2). Other available ligands, e.g., SPhos (L2) and XPhos (L3) provided lower yields when Pd2(dba)3 was used as a catalyst, even after longer reaction time (Table 1, entries 3 and 4). By using Pd(OAc)2 as a catalyst and SPhos (L2) and XPhos (L3) as a bidentate ligand, low to moderate yields were

Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

• Gianluigi Broggini,
• Egle M. Beccalli,
• Andrea Fasana and
• Silvia Gazzola

Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198

• rearrangement that is operative during the alkylation of indoles [46]. In 1969, Fujiwara and Moritani reported the alkenylation of arenes catalyzed by Pd(OAc)2, using Cu(OAc)2 or AgOAc as oxidants [47]. This strategy provides a convenient method for the synthesis of olefins linked to heteroarenes, including

• indole, furan, and benzofuran rings (Scheme 2) [48]. Working with indole and methyl acrylates in the presence of Pd(OAc)2 and 1,4-benzoquinone in catalytic quantity with tert-butyl hydroperoxide as oxidant, 3-alkenyl-substituted products were obtained. The synthetic value of the direct catalytic C–H

• -substituted indoles. Coupling of indole and 2-methyl-2-butene in the presence of Pd(OAc)2 (40 mol %), Cu(OAc)2 and AgOTf as the co-oxidants in MeCN constitutes a simple route to N-prenylated indoles 8 (Scheme 7) [54]. This mild reaction, which exhibits broad functional-group tolerance, can be successfully

Synthesis of 5-oxyquinoline derivatives for reversal of multidrug resistance

• Torsten Dittrich,
• Nils Hanekop,
• Nacera Infed,
• Lutz Schmitt and
• Manfred Braun

Beilstein J. Org. Chem. 2012, 8, 1700–1704, doi:10.3762/bjoc.8.193

• (OAc)2, t-Bu3P, toluene, reflux, 16 h; 3c: 76%; 4c: 41%. Relative transport activity of LmrCD and Pdr5 in the presence of zosuquidar (1a) and selected new 5-oxyquinoline derivatives (2a–13a).a Supporting Information Supporting Information File 236: Procedures. Spectroscopic and analytical data

• h; 72%. (b) 5-hydroxyquinoline, K2CO3, DMF, 25 °C, 20 h; 67%. (c) EtOH, reflux, 3 h; 2a: 72%; 3a: 72%; 4a: 69%; 5a: 83%; 6a: 79%; 7a: 77%; 8a: 98%; 9a: 61%; 10a: 83%; 11a: 72%; 12a: 90%; 13a: 29%. Preparation of N-Boc-protected 4-aminopiperidines 3c and 4c. Reagents and conditions: (a) NaOt-Bu, Pd

Extending the utility of [Pd(NHC)(cinnamyl)Cl] precatalysts: Direct arylation of heterocycles

• Anthony R. Martin,
• Anthony Chartoire,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2012, 8, 1637–1643, doi:10.3762/bjoc.8.187

• derivatives. To complete the study, experiments were performed at lower catalyst loading using imidazopyridine (13). This class of substrate has recently been involved, by Doucet et al. [45], in direct arylation with a catalytic charge of Pd(OAc)2 ranging from 0.1 to 0.01 mol %. In our case, comparable yields