Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• -order dependence on alkene, first-order dependence on catalyst, and second-order dependence on the imidazolidinone nucleophile [22]. They observed a primary kinetic isotope effect (k(H/D) = 3.14) when deuterated amine was used. The second order dependence is rationalized by a mechanism where a second

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• -imidazolidinone) [26] additive was used as polar aprotic solvent, which also increases the homogeneity of the reaction mixture. In the first reaction, 1.1 equiv of tropylium NTf2 were used. The reaction worked at room temperature and after 16 h the product 3a was isolated in low 22% yield and a 2:1 diastereomeric

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

Synthesis of a novel aminobenzene-containing hemicucurbituril and its fluorescence spectral properties with ions

• Qingkai Zeng,
• Qiumeng Long,
• Jihong Lu,
• Li Wang,
• Yuting You,
• Xiaoting Yuan,
• Qianjun Zhang,
• Qingmei Ge,
• Hang Cong and
• Mao Liu

Beilstein J. Org. Chem. 2021, 17, 2840–2847, doi:10.3762/bjoc.17.195

• reduction of 5-nitroisophthalic acid with NaBH4 and BF3·Et2O followed by subsequent bromination with PBr3 [46] and 2-imidazolidinone (6) were used as building blocks. By controlling the molar ratio of 5 and 6 at 1:10 or 6:1 and the reaction conditions, products 7 and 8 were readily accessible with 25.3

• imidazolidinone components were observed at rt. This indicated that the formed macrocycle is highly symmetric in solution. After successful construction of macrocycle 9, the aminobenzene-containing hemicucurbituril 4 was obtained by reduction of the nitro groups in 9 with Fe powder in H2O/EtOH at 86 °C for 2 h

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• , an excess of sodium thioalkoxide in 1,3-dimethyl-2-imidazolidinone 98 reacted with 94 at 100 °C to generate the required sumanene derivatives 99a–c. In another report, Sakurai’s group in situ generated sumanyne and treated it with different dienes (101a–d) in a Diels–Alder (DA) manner to produce the

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

Fluorinated phenylalanines: synthesis and pharmaceutical applications

• Laila F. Awad and
• Mohammed Salah Ayoup

Beilstein J. Org. Chem. 2020, 16, 1022–1050, doi:10.3762/bjoc.16.91

• pentafluoro-ʟ-phenylalanine derivatives 24a–c, respectively [41] (Scheme 5). The stereoselective benzylation of (S)-imidazolidinone ((S)-Boc-BMI) 25 with tetrafluorobenzyl bromides 26a,b afforded the benzylated imidazolidinones 27a,b. The acidic hydrolysis of 27a,b with simultaneous deprotection to release

• (nPt: neopentyl, TCE: trichloroethyl). Synthesis of ʟ-4-[sulfono(difluoromethyl)]phenylalanine derivatives 17. Synthesis of fluorinated Phe analogues from Cbz-protected aminomalonates. Synthesis of tetrafluorophenylalanine analogues via the 3-methyl-4-imidazolidinone auxiliary 25. Synthesis of

Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas

• Zhenghui Liu,
• Peng Wang,
• Zhenzhong Yan,
• Suqing Chen,
• Dongkun Yu,
• Xinhui Zhao and
• Tiancheng Mu

Beilstein J. Org. Chem. 2020, 16, 645–656, doi:10.3762/bjoc.16.61

• (PMP)), and solvents (N,N-dimethylacetamide (DMA), 1,3-dimethyl-2-imidazolidinone (DMI), N-methyl-2-pyrrolidinone (NMP), tetrahydrofuran (THF), 1,4-dioxane, ethanol, methanol, acetonitrile, and toluene) together with aryl iodides and other reagents were purchased from commercial sources (namely J&K

Synthesis of disparlure and monachalure enantiomers from 2,3-butanediacetals

• Adam Drop,
• Hubert Wojtasek and
• Bożena Frąckowiak-Wojtasek

Beilstein J. Org. Chem. 2020, 16, 616–620, doi:10.3762/bjoc.16.57

• enantioselective reactions, such as the Sharpless epoxidation [19][20][21][22][23][24], asymmetric dihydroxylation [25][26], chloroallyloboronation [27], or iodolactonization [28]. Most recently a method using the asymmetric chlorination of dodecanal by LiCl in the presence of a chiral imidazolidinone catalyst has

α-Photooxygenation of chiral aldehydes with singlet oxygen

• Dominika J. Walaszek,
• Magdalena Jawiczuk,
• Jakub Durka,
• Olga Drapała and
• Dorota Gryko

Beilstein J. Org. Chem. 2019, 15, 2076–2084, doi:10.3762/bjoc.15.205

• predominates while the imidazolidinone-catalyzed reaction is (S)-enantioselective. Nevertheless, the scope is limited to simple, achiral aldehydes. As the synthesis of more complex targets often requires functionalization of molecules with stereocenters being already installed, we wondered whether and how

• ]. For that reason, for our optimization studies we used enantioenriched aldehyde 1 (S/R 2:1 mixture of enantiomers) formed in the photochemical reaction of cinnamaldehyde (12) with benzyltrimethylsilane (BnTMS, 13) catalyzed by commercially available imidazolidinone cis-14 (Scheme 3) [16]. Aldehyde 1

• was subjected to photooxygenation in the presence of various organocatalysts: amide 15, imidazolidinone 16, diarylprolinol silyl ethers (S)-17 and (S)-18 which proved the most effective in the photooxygenation of achiral 3-phenylpropanal (Table 1) [14]. The prolinamide-catalyzed reaction furnished

Naphthalene diimides with improved solubility for visible light photoredox catalysis

• Barbara Reiß and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 2043–2051, doi:10.3762/bjoc.15.201

• ) is one of the benchmark reactions for photoredox catalysis because it combines photoredox catalysis with organocatalysis [53]. Initially, [Ru(bpy)3]Cl2 was applied by MacMillan et al. as photoredox catalyst together with the chiral imidazolidinone 15 as organocatalyst to achieve enantioselectivity

Green synthesis of new chiral 1-(arylamino)imidazo[2,1-a]isoindole-2,5-diones from the corresponding α-amino acid arylhydrazides in aqueous medium

• Nadia Bouzayani,
• Jamil Kraїem,
• Sylvain Marque,
• Yakdhane Kacem,
• Abel Carlin-Sinclair,
• Jérôme Marrot and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2018, 14, 2923–2930, doi:10.3762/bjoc.14.271

• imino-carboxylic acid form likely evolves to its iminium-carboxylate form B [50]. This last intermediate involves the existence of two possible transition states for the cyclization of the imidazolidinone core of which one of them is favored by an intramolecular hydrogen bond (Scheme 5). This control is

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

Synthesis of 1,3-cis-disubstituted sterically encumbered imidazolidinone organocatalysts

• Jan Wallbaum and
• Daniel B. Werz

Beilstein J. Org. Chem. 2017, 13, 2577–2583, doi:10.3762/bjoc.13.254

• Jan Wallbaum Daniel B. Werz Institut für Organische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany 10.3762/bjoc.13.254 Abstract A variety of novel imidazolidinone-based organocatalysts with bulky substituents were synthesized under mild reaction conditions

• starting from easily accessible substrates. Different natural and unnatural amino acid methyl amides were cyclized with aromatic carbaldehydes to yield two diastereomeric MacMillan-type catalysts. Special emphasis was put on bulky residues such as mesityl and pyrene moieties. Keywords: imidazolidinone

• ][3][4][5][6][7]. Initially, proline and proline-derived catalysts have been widely used in asymmetric iminium and enamine organocatalysis [8][9][10][11][12]. Since the beginning of the 21th century imidazolidinone-based organocatalysts developed by MacMillan and co-workers, which are easily

Comparative profiling of well-defined copper reagents and precursors for the trifluoromethylation of aryl iodides

• Peter T. Kaplan,
• Jessica A. Lloyd,
• Mason T. Chin and
• David A. Vicic

Beilstein J. Org. Chem. 2017, 13, 2297–2303, doi:10.3762/bjoc.13.225

• in Scheme 1. Conditions for C1: [(PPh3)3Cu(CF3)] + dtbpy: toluene, 80 °C. Conditions for A1: [(SIMes)Cu(CF3)] and A2 ([(SIMes)Cu(O-t-Bu)] + TMSCF3: DMI/benzene (1.5:7.5), 50 °C. DMI = 1,3-dimethyl-2-imidazolidinone. Conditions for B2: [(Cu(O-t-Bu)]4 + phen +TMSCF3: DMF, 50 °C. Yields were monitored

Continuous N-alkylation reactions of amino alcohols using γ-Al₂O₃ and supercritical CO₂: unexpected formation of cyclic ureas and urethanes by reaction with CO₂

• Emilia S. Streng,
• Darren S. Lee,
• Michael W. George and
• Martyn Poliakoff

Beilstein J. Org. Chem. 2017, 13, 329–337, doi:10.3762/bjoc.13.36

• expected to produce high selectivity for the corresponding imidazolidinone 16 via the incorporation of CO2. The competing oxazolidinone formation should be limited as the nucleophilicity of nitrogen is more than that of the oxygen. Furthermore, the formation of dimers were expected to be supressed as 16

• does not contain a “CO2 unit” that can serve as a leaving group. This was indeed the case as, at 250 °C, 85% selectivity, 70% yield for 16 was observed when the reaction was run in scCO2 (Scheme 3a). In the absence of CO2 as a solvent the formation of imidazolidinone 16 was not observed. When the

• (Scheme 3b, 380 °C at 1 mL min−1), and no imidazolidinone 16 was detected. Conclusion Using a self-optimising reactor and a simple heterogeneous catalyst, γ-Al2O3, moderate to high yields of several alkylated cyclic amines, formed in a two-step intramolecular cyclisation/N-alkyation reaction, using amino

An effective one-pot access to polynuclear dispiroheterocyclic structures comprising pyrrolidinyloxindole and imidazothiazolotriazine moieties via a 1,3-dipolar cycloaddition strategy

• Alexei N. Izmest’ev,
• Galina A. Gazieva,
• Natalya V. Sigay,
• Sergei A. Serkov,
• Valentina A. Karnoukhova,
• Vadim V. Kachala,
• Alexander S. Shashkov,
• Igor E. Zanin,
• Angelina N. Kravchenko and
• Nina N. Makhova

Beilstein J. Org. Chem. 2016, 12, 2240–2249, doi:10.3762/bjoc.12.216

• of these two bands, one broad band is observed), and 1649–1634 cm−1 that are characteristic of oxindole, imidazolidinone, and thiazolidinone ring carbonyl groups. The 1H NMR spectra of compounds 4 exhibited, along with the proton signals of the imidazothiazolotriazine and oxindole moieties, the

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• variety of proline polymers and proline amphiphiles, on large scale, from hydroxyproline (Scheme 9) [46]. The work was later extended into a generalized system for polymeric immobilization of proline, prolineamide, diarylprolinol and imidazolidinone chiral organocatalysts by copolymerization of a set of

One-pot functionalisation of N-substituted tetrahydroisoquinolines by photooxidation and tunable organometallic trapping of iminium intermediates

• Joshua P. Barham,
• Matthew P. John and
• John A. Murphy

Beilstein J. Org. Chem. 2014, 10, 2981–2988, doi:10.3762/bjoc.10.316

• ). Vinylogous nucleophilic addition of the enamine to 5a generates 8a. This hypothesis is supported by the reaction of 5a with crotonaldehyde in the presence of a MacMillan-type imidazolidinone catalyst [41] and TFA which delivers 8b. Formation of cyclic products 8b and 9 is rationalised by intramolecular

Solid-phase-supported synthesis of morpholinoglycine oligonucleotide mimics

• Tatyana V. Abramova,
• Sergey S. Belov,
• Yulia V. Tarasenko and
• Vladimir N. Silnikov

Beilstein J. Org. Chem. 2014, 10, 1151–1158, doi:10.3762/bjoc.10.115

• ’-tetramethyluronium tetrafluoroborate, 1-methyl-2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone (Sigma-Aldrich, USA); Boc-Gly-PAM resin (substitution 0.76 mmol/g, NovaBiochem, Germany); sodium azide, glycine (Serva, Germany); sodium periodate, bromotrichloromethane, di-tert-butyl dicarbonate (Acros Organics, USA

Non-cross-linked polystyrene-supported 2-imidazolidinone chiral auxiliary: synthesis and application in asymmetric alkylation reactions

• Quynh Pham Bao Nguyen and
• Taek Hyeon Kim

Beilstein J. Org. Chem. 2013, 9, 2113–2119, doi:10.3762/bjoc.9.248

• -imidazolidinone chiral auxiliaries were successfully investigated with excellent diastereocontrol (>99% de). The recovery and the recycling of this soluble polymer-supported chiral auxiliary were achieved in order to produce highly optical pure carboxylic acids. Keywords: asymmetric alkylation; chiral

• auxiliaries; chiral carboxylic acids; 2-imidazolidinone; non-cross-linked polystyrene; Introduction Chiral auxiliaries have been proven as a powerful tool for the asymmetric synthesis of highly optical pure compounds used in pharmaceuticals or agrochemicals [1][2]. The recycling and reuse of expensive chiral

• polystyrene (NCPS)-supported 2-phenylimino-2-oxazolidine, which facilitated the synthesis of several chiral amides in excellent stereoselectivity (>96% ee). However, the sterically undemanding methylation has not been investigated [20]. Recently, we introduced 2-imidazolidinone [26][27], a versatile auxiliary

Thiourea-catalyzed Diels–Alder reaction of a naphthoquinone monoketal dienophile

• Carsten S. Kramer and
• Stefan Bräse

Beilstein J. Org. Chem. 2013, 9, 1414–1418, doi:10.3762/bjoc.9.158

• ). At first, the use of MacMillan's imidazolidinone organocatalyst 6 [12] was examined, but no catalytic effect was observed (Table 2, entry 2). The usage of L-proline as a bifunctional catalyst only gave a slight improvement compared to the uncatalyzed reaction (Table 2, entry 3). Whereas the addition

Enantioselective total synthesis of (R)-(−)-complanine

• Krystal A. D. Kamanos and
• Jonathan M. Withey

Beilstein J. Org. Chem. 2012, 8, 1695–1699, doi:10.3762/bjoc.8.192

• MacMillan imidazolidinone (5R)-2,2,3-trimethyl-5-benzyl-4-imidazolidinone [8] with 4-nitrobenzoic acid as cocatalyst, all efforts to effect benzoylation of 3, yielding 5, were unsuccessful, and this route was ultimately abandoned as attention turned to more conventional α-oxygenation strategies and a

A quantitative approach to nucleophilic organocatalysis

• Herbert Mayr,
• Sami Lakhdar,
• Biplab Maji and
• Armin R. Ofial

Beilstein J. Org. Chem. 2012, 8, 1458–1478, doi:10.3762/bjoc.8.166

• pericyclic reactions with the iminium ions and therefore do not follow Equation 1 [53]. Let us now consider the role of counterions, as the imidazolidinone catalyzed reactions of cinnamaldehyde with pyrrole were reported to proceed with high yields and enantioselectivities, when using trifluoroacetic acid as

• ether [81], had previously been synthesized and characterized (X-ray structure) by Seebach et al. [30], neat samples of the imidazolidinone-derived enamines 32c–32e became only recently available by TsOH-catalyzed condensation of phenylacetaldehyde with the corresponding imidazolidinones and column

• nucleophilicities of the imidazolidinone derived enamines, which are in line with the larger 13C NMR chemical shifts of C-2 in 32d (101.9 ppm) and 32e (102.9 ppm) compared to that of C-2 in 32a (97.4 ppm), are not only due to the electron-withdrawing effect of the additional heteroatoms in the heterocyclic rings