1-Imidoalkylphosphonium salts with modulated C_α–P⁺ bond strength: synthesis and application as new active α-imidoalkylating agents

• Jakub Adamek,
• Roman Mazurkiewicz,
• Anna Węgrzyk and
• Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

• . The crucial step in the method included the decarboxylative α-methoxylation of N-phthaloyl- or N-succinylamino acids to the corresponding N-(1-methoxyalkyl)imides, followed by the displacement of the methoxy group by the triarylphosphonium group through melting of the imide derivative with

• facilitates the cleavage of the highly polar Cα–P+ bond. Keywords: N-(1-arylalkyl)imides; α-imidoalkylating agents; imidoalkylation reactions; 1-imidoalkylphosphonium salts; Tscherniac–Einhorn-type reaction; Introduction The aminomethylation of C–H acidic compounds by the condensation of non-enolizable

• aromatic systems with strong electron-donating substituents (e.g., alkoxy-, polyalkoxy- and aminoarenes), or some activated heterocyclic systems such as indole [3][8][10][24][25]. The α-imidoalkylation reaction using N-(1-hydroxyalkyl)imides (almost entirely N-hydroxymethylphthalimide) in sulfuric acid

Brønsted acid-mediated cyclization–dehydrosulfonylation/reduction sequences: An easy access to pyrazinoisoquinolines and pyridopyrazines

• Ramana Sreenivasa Rao and
• Chinnasamy Ramaraj Ramanathan

Beilstein J. Org. Chem. 2017, 13, 428–440, doi:10.3762/bjoc.13.46

• preparation of piperazine-2,6-dione derivatives from N-benzenesulfonyliminodiacetic acid at room temperature. After careful reviewing of reagents for amide bond formation, the reagent CDI proved to be a very successful reagent for the preparation of imides, amides, esters and thioesters. Therefore, the

• obtained in 72% yield at room temperature in the presence of 10 mol % of DMAP. Similarly, this strategy has been extended to couple various arylethylamines with N-benzenesulfonyliminodiacetic acid at room temperature to furnish expected imides 7a–h in good yields (Scheme 2). The successful development of

• the potassium salt of N-benzyliminodiacetic acid in THF at reflux to furnish the expected imides 8a–c, 8h, and 8i in good yields (Scheme 6). The imide 8h was subjected to the cyclization reaction conditions using 6 equivalents of TfOH under neat conditions at 70 °C followed by reduction using NaBH4

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• manifold might possibly operate via different pathways. α,β-Unsaturated imides Lewis acids The catalytic generation of enolates in situ, while aesthetically attractive, presents its own set of challenges due to the potential for both E- and Z-enolate isomers that in some cases equilibrate under the

• reaction conditions. In this context, α,β-unsaturated imides are attractive substrates for conjugate addition–enantioselective protonation sequences. Imides are not only more electron withdrawing than esters, but the presence of a second carbonyl also provides an additional point of contact through which

• formed from Zn(NTf2)2 and Ph-dbfox ligand (S)-85, pyrroles 83 were added to imides 84 to produce 85 in high yield and modest to excellent enantioselectivity. Exploring a number of achiral imides, the authors found that an isoxazolidinone auxiliary enhanced the reactivity and minimized enolate A1,3

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• [68], most efforts still focus on the development of unsaturated ester/amide surrogates [69][70][71], which involve α,β-unsaturated imides, N-acyl heterocycles, α-oxophosphonates, α-ketoesters, 3-methyl-4-nitro-5-alkenylisoxazoles and α’-hydroxyenones. These latter substrates have proven to be very

Cupreines and cupreidines: an established class of bifunctional cinchona organocatalysts

• Laura A. Bryant,
• Rossana Fanelli and
• Alexander J. A. Cobb

Beilstein J. Org. Chem. 2016, 12, 429–443, doi:10.3762/bjoc.12.46

• utilized a 9-OH benzoyl derivatised cupreine CPN-38 to effect a Friedel-Crafts reaction of 2-naphthols 36 with benzoxathiazine 2,2-dioxides 37 (Scheme 10). These cyclic imides, derived from salicylic aldehydes, have a rigid structure which prevents E/Z-isomerization, allowing for greater control over the

Recent advances in copper-catalyzed C–H bond amidation

• Jie-Ping Wan and
• Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

• reaction at 100 °C allowed the synthesis of various N-alkylamides, sulfonamides and imides with fair to excellent yield, and the results also suggested that the catalytic method tended to selectively enable the transformation of secondary or primary C–H bonds, while the amidation of the tertiary alkyl C–H

• catalysis of CuBr and NBS. By simply stirring at rt, 75 or 90 °C, a variety of primary amides and lactams incorporated aldehydes 57 to yield imides 58 with moderate to excellent yield. In addition, the method also displayed sound application in the synthesis of cyclic imides such as N-methylphthalimide (60

• ) via the intramolecular amidation of N-methyl-o-formylbenzamide (59) (Scheme 16). More recently, Lan et al. [66] realized the C–H amidation of N,N-dialkylformamides 61 using pyridine-2-yl-functionalized amides 62 or 63. Under catalytic conditions consist of CuBr and TBHP, imides 64 and 65 were afforded

Radical-mediated dehydrative preparation of cyclic imides using (NH₄)₂S₂O₈–DMSO: application to the synthesis of vernakalant

• Dnyaneshwar N. Garad,
• Subhash D. Tanpure and
• Santosh B. Mhaske

Beilstein J. Org. Chem. 2015, 11, 1008–1016, doi:10.3762/bjoc.11.113

• convenient one-pot process for the synthesis of miscellaneous cyclic imides in high yields starting from readily available primary amines and cyclic anhydrides. A plausible radical mechanism involving DMSO has been proposed. The application of this facile one-pot imide forming process has been demonstrated

• for a practical synthesis of vernakalant. Keywords: APS-DMSO; imides; practical synthesis; radical-mediated; vernakalant; Introduction Cyclic imides are privileged pharmacophores and important building blocks for the synthesis of natural products, drugs, agrochemicals, advanced materials and

• polymers. Migrastatin, lamprolobine, julocrotine, cladoniamide A, palasimide and salfredin C-1 are few of the important natural products having the imide motif [1][2][3][4]. Imides have been extensively used in the synthesis of several bioactive natural products [5][6][7][8][9][10][11][12]. Various drugs

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• to excellent yields and enantioselectivities. In 2006, Pineschi and co-workers reported the copper-catalyzed asymmetric 1,4-addition of alkylzinc reagents to acyclic α,β-unsaturated imides [95]. In this case, the authors used a phosphoramidite as the chiral ligand. They were also able to obtain the

• been discussed. Gandelman and Jacobsen reported the first asymmetric 1,4-addition of various N-heterocycles to α,β-unsaturated imides [246]. This reaction represented a novel approach to synthesizing functionalized chiral N-heterocycles, which are studied in areas such as material science [247][248

• ] and biological chemistry [249][250][251][252]. In the past, the Jacobsen group has used chiral (salen)Al complexes [253] as catalysts for the asymmetric 1,4-addition of azide [254], cyanide [219], substituted nitriles [255] and oximes [256] to α,β-unsaturated imides. The authors used these previous

Chiral phosphines in nucleophilic organocatalysis

• Yumei Xiao,
• Zhanhu Sun,
• Hongchao Guo and
• Ohyun Kwon

Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218

• corresponding γ-cycloadduct as the major product in 92% yield, with 9:1 dr and 74% ee [77]. Using the amino acid-derived chiral phosphine catalyst H11, Lu and co-workers performed asymmetric [3 + 2] annulations between MBH carbonates and maleimides, obtaining access to a wide range of bicyclic imides in

Direct and indirect single electron transfer (SET)-photochemical approaches for the preparation of novel phthalimide and naphthalimide-based lariat-type crown ethers

• Dae Won Cho,
• Patrick S. Mariano and
• Ung Chan Yoon

Beilstein J. Org. Chem. 2014, 10, 514–527, doi:10.3762/bjoc.10.47

• imides; Review Since the 1970s, studies by a number of organic photochemists have demonstrated that a large number of unique single electron transfer (SET) mechanistic pathways are followed in photochemical reactions [1][2][3][4][5][6][7][8][9][10]. Owing to its potentially large energetic driving force

• ether-terminated, polydonor-linked, imides can be employed as key steps in the synthesis of novel, lariat-type crown ethers. In parallel efforts focusing on bis-donor-linked bis-phthalimides, we have developed a novel strategy for the preparation of bis-crown ethers (Scheme 13) [84]. In these studies

• results in a close facial approach of the benzamide aromatic rings in 60, which results in intramolecular exciplex formation (Scheme 16). Conclusion Direct and indirect approaches, which rely on the use of SET-promoted photocyclization reactions of α-silyl ether-terminated, polydonor-linked, imides (e.g

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

• . Tandem aza-[4 + 2]-cycloaddition/allylboration/retrosulfinyl-ene sequence. Boronated heterodendralene 32 in [4 + 2]-cycloadditions. Synthesis of tricyclic imides derivatives. Synthesis of 37 via a HDA/allylboration/DA sequence. Diels–Alder/allylboration sequence. Acknowledgements L.E. thanks the Durham

Coupling of C-nitro-NH-azoles with arylboronic acids. A route to N-aryl-C-nitroazoles

• Marta K. Kurpet,
• Aleksandra Dąbrowska,
• Małgorzata M. Jarosz,
• Katarzyna Kajewska-Kania,
• Nikodem Kuźnik and
• Jerzy W. Suwiński

Beilstein J. Org. Chem. 2013, 9, 1517–1525, doi:10.3762/bjoc.9.173

• substrates such as amines, amides, imides or heterocycles with boronic acids, the method has become a powerful synthetic route for N-arylation. Many investigations concerning the influence of the amount and kind of a catalyst, type of solvent, temperature, the presence of a base, and other reaction

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• to the design of new protocols for the activation of N-hydroxy imides in the presence of nonmetal initiators. Herein we provide a concise overview of the most significant and successful examples in this field, with the final aim to furnish a useful instrument for all scientists actively involved in

• detrimental for the selectivity of the process and they would not meet the standards of “green chemistry”. An alternative catalytic route is based on the use of N-hydroxy imides (NHIs), and in particular N-hydroxyphthalimide (NHPI), which have found ample application as ideal catalysts for the aerobic

• catalyzed by N-hydroxyphthalimide and analogous N-hydroxy imides is becoming an essential tool for all research groups directly involved in the development of selective transformations mediated by molecular oxygen. This increasing interest is testified by several papers that have appeared in the past few

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

• Maurizio Fagnoni,
• Stefano Protti,
• Davide Ravelli and
• Angelo Albini

Beilstein J. Org. Chem. 2013, 9, 800–808, doi:10.3762/bjoc.9.91

• Maurizio Fagnoni Stefano Protti Davide Ravelli Angelo Albini PhotoGreen Lab, Department of Chemistry, University of Pavia, V. Le Taramelli 12, 27100 Pavia, Italy 10.3762/bjoc.9.91 Abstract Steady-state irradiation in neat acetonitrile of some aromatic nitriles, imides and esters (10−5–10−3 M

• study were nitriles, viz. 1,2,4,5-tetracyanobenzene (TCB), 1,3,5-tricyanobenzene (1,3,5-TrCB), 1,2,4-tricyanobenzene (1,2,4-TrCB), 1,4-dicyanonaphthalene (DCN), 9,10-dicyanoanthracene (DCA); imides, viz. 4,5-dicyanophthalimide (DCP), and its N-methylated derivative (DCP-Me); and esters (methyl

A facile, rapid, one-pot regio/stereoselective synthesis of 2-iminothiazolidin-4-ones under solvent/scavenger-free conditions

• Murugan Sathishkumar,
• Sangaraiah Nagarajan,
• Poovan Shanmugavelan,
• Murugan Dinesh and
• Alagusundaram Ponnuswamy

Beilstein J. Org. Chem. 2013, 9, 689–697, doi:10.3762/bjoc.9.78

• environmentally friendly methodologies for the synthesis of 2-iminothiazolidin-4-ones is worth attempting. In this regard, and in continuation of our recent reports on the solvent-free synthesis of amides [19][20], thioamides [21], cyclic imides [22], thiazolidin-4-ones [23], spirothiazolidin-4-ones [24], 1,2,3

New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin

• Adam Mondrzyk,
• Beate Mondrzik,
• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2118–2123, doi:10.3762/bjoc.8.238

• functional groups, such as nitrones, double bonds and imides, have been synthetized and investigated in our group [14][15][16][17][18]. There are also several natural phenols such as flavonoides, or isoflavonoides, which were also polymerized successfully [19]. 4-Ferrocenylphenol (2) has been the subject of

Metal–ligand multiple bonds as frustrated Lewis pairs for C–H functionalization

• Matthew T. Whited

Beilstein J. Org. Chem. 2012, 8, 1554–1563, doi:10.3762/bjoc.8.177

• ] cycloreversion (Scheme 4) [28]. Other early metal imides may demonstrate similar reactivity, as seen in a reaction reported by Schrock for a tantalum(V) imide [29]. The reactions described above represent only a few of the many metal–ligand cooperative reactions of nucleophilic, multiply bonded species with

• ) and related variants such as alkyne and enyne metathesis [36][37]. Related reactivity is prevalent for other Mδ+═Eδ− species such as imides and nitrides. Bergman's bis(cyclopentadienyl)zirconium(IV) imides, described above, will add alkenes and alkynes in [2 + 2] fashion across the Zr═NR bond (Scheme

• -atom or nitrene-group transfer and formation of (PNP)Ir–N2 [78], and this reaction was utilized in catalytic C–H functionalization (see below). More recently, Hillhouse's nickel carbenes and imides have been shown to exhibit similar reactivity with organic azides, though reaction with CO2 has not been

Improved syntheses of high hole mobility phthalocyanines: A case of steric assistance in the cyclo-oligomerisation of phthalonitriles

• Daniel J. Tate,
• Rémi Anémian,
• Richard J. Bushby,
• Suwat Nanan,
• Stuart L. Warriner and
• and Benjamin J. Whitaker

Beilstein J. Org. Chem. 2012, 8, 120–128, doi:10.3762/bjoc.8.14

• schematically in Scheme 2. In the intermediates 8 (Scheme 2, X = C5H11O, Y = growing oligomer chain) the exocyclic carbon/nitrogen double bond marked * presumably has the (Z)-stereochemistry shown. This is the favoured stereochemistry for most imides of aromatic ketones, although the opposite stereochemisty is

Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

• Carolin Fischer and
• Burkhard Koenig

Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10

• temperature [35][36] and in aqueous solution [37]. However, the reactions are very slow and require several hours or even days for completion [38]. In general, there are a wide variety of protocols describing the metal-mediated arylation of amines [17][37][39], amides [38], imides [38], imidazoles [14][37][40

Brønsted acid-promoted azide–olefin [3 + 2] cycloadditions for the preparation of contiguous aminopolyols: The importance of disiloxane ring size to a diastereoselective, bidirectional approach to zwittermicin A

• Hubert Muchalski,
• Ki Bum Hong and
• Jeffrey N. Johnston

Beilstein J. Org. Chem. 2010, 6, 1206–1210, doi:10.3762/bjoc.6.138

• benzyl azide with α,β-unsaturated imides. Using a strong Brønsted acid (triflic acid) to activate the electron deficient imide π-bond, high diastereoselection was observed provided that a 1,1,3,3-tetraisopropoxydisiloxanylidene group (TIPDS) is used to restrict the conformation of the central 1,3-anti

Acid- mediated reactions under microfluidic conditions: A new strategy for practical synthesis of biofunctional natural products

• Katsunori Tanaka and
• Koichi Fukase

Beilstein J. Org. Chem. 2009, 5, No. 40, doi:10.3762/bjoc.5.40

• reactive sialyl donors having C-5 cyclic imides (Table 1), especially N-phthalimide 1a, by virtue of the “fixed-dipole moment effects” (α-only, 92% on 50 mg scale) [41]. The scale-up in a batch process, however, significantly decreased the yield and selectivity. Thus, a 100 mg scale reaction of 1a gave

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• the requisite 5-halopyrrolidinone precursor. 5.5. Cha. Dialkoxytitanacyclopropane addition to imides This methodology provides a very elegant way to install the C9a hydroxyl group, which remains the biggest challenge of mitomycin synthesis. Based on the precedent of ester cyclopropanation in presence

N-Arylation of amines, amides, imides and sulfonamides with arylboroxines catalyzed by simple copper salt/EtOH system

• Zhang-Guo Zheng,
• Jun Wen,
• Na Wang,
• Bo Wu and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2008, 4, No. 40, doi:10.3762/bjoc.4.40

• , imides and sulfonamides catalyzed by a copper salt/EtOH system has been developed. In the absence of a base or additive the corresponding N-arylation products were obtained in moderate to excellent yields. Keywords: N-arylation; arylboroxine; copper salt; cross-coupling; ethanol; Introduction The

• ]. Moreover, the reaction rates of these reactions were generally slow, even requiring 3 d for completion [5][6][7]. An attractive alternative to this approach is to develop a simple and efficient catalytic system under mild reaction conditions. Thus, a simple copper salt-catalyzed N-arylation of imides with

• ). Furthermore, we expand the substrate scope of this reaction: a variety of amines, amides, imides and sulfonamides with arylboroxine can also participate in this catalytic system to give the corresponding N-arylation products in moderate to excellent yields. To the best of our knowledge, N-arylation of NH

Total synthesis of the indolizidine alkaloid tashiromine

• Stephen P. Marsden and
• Alison D. McElhinney

Beilstein J. Org. Chem. 2008, 4, No. 8, doi:10.1186/1860-5397-4-8

• sidechain found in tashiromine. The synthesis of azabicyclic assemblies by intramolecular allylsilane/N-acyliminium cyclisations was first studied by Hiemstra and Speckamp [16], who prepared their functionalised allylsilane cyclisation precursors (such as 3) by alkylation of cyclic imides with reagent 4 (X