Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• enantioselective aza-Friedel–Crafts addition. In the first step, the DDQ-promoted oxidation of 3-indolinonecarboxylate 22 generated indolenines that performed as the potential electrophiles towards indoles 4. The chiral catalyst effectively assembled the reacting partners in a chiral transition state through H

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

• the stereogenic centers formed during the cascade cyclization was secured by the use of benzothiophene-based TADDOL thiol 166 as chiral catalyst. They obtained in one single step a 5.3:1 and 3.4:1 diastereomeric ratio for C14 and C15, respectively, while forming the desired trans [5-8] ring junction

Total synthesis of grayanane natural products

• Nicolas Fay,
• Rémi Blieck,
• Cyrille Kouklovsky and
• Aurélien de la Torre

Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181

• authors showed that a key intermediate could be obtained enantioselectively (93% ee) by a combination of a chiral catalyst and chiral auxiliary, although requiring extra steps for auxiliary installation and cleavage. Scheme 12 summarizes the last 3 synthetic strategies for grayanane synthesis. Each group

Mechanochemical synthesis of unsymmetrical salens for the preparation of Co–salen complexes and their evaluation as catalysts for the synthesis of α-aryloxy alcohols via asymmetric phenolic kinetic resolution of terminal epoxides

• Shengli Zuo,
• Shuxiang Zheng,
• Jianjun Liu and
• Ang Zuo

Beilstein J. Org. Chem. 2022, 18, 1416–1423, doi:10.3762/bjoc.18.147

• reaction and stirred for 18 hours at 0 °C. Upon the reaction completion, 3-chloro-1,2-propanediol in highly enantioenriched structure was afforded using chiral catalyst 2f, while non-chiral catalysts 2e and 2g displayed nonenantioselective results (Table 2). To broaden the use of our chiral catalyst, α

Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

• Sayan Pramanik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

• operation without chiral catalyst is still an atom-economical and operationally simple procedure to demonstrate the construction of dispirooxindoles. In the recent years, the diastereoselective construction of dispirocyclopentanebisoxindoles consisting of two spirooxindole motifs has acquired attention from

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• reactions, and enzymatic rearrangements. Review Asymmetric α-ketol rearrangements One major advancement in the field of α-ketol rearrangements is the development of methods for performing the reaction asymmetrically. This is possible by two approaches: (1) stereoselectively through the use of a chiral

• catalyst in the presence of a substrate possessing a prochiral migrating group or (2) stereospecifically by means of a chiral α-ketol. As an example of an enantioselective rearrangement, complexes of nickel(II) with a series of chiral 1,2-diaminopropane or pyridineoxazoline ligands were evaluated for their

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• study [41][42] in 2017. This metal-catalyzed, photoinduced, and asymmetric radical transformation requires two catalysts, namely, (i) a metal catalyst that promotes electron transfer and (ii) a separate chiral catalyst that facilitates the highly stereoselective bond formation. In 2016, Fu [82

Enantioselective PCCP Brønsted acid-catalyzed aminalization of aldehydes

• Martin Kamlar,
• Robert Reiberger,
• Martin Nigríni,
• Ivana Císařová and
• Jan Veselý

Beilstein J. Org. Chem. 2021, 17, 2433–2440, doi:10.3762/bjoc.17.160

• -workers, using an (S)-TRIP derivative as the chiral catalyst (Figure 1) [14]. Soon after, Rueping et al. developed a similar methodology catalyzed by other chiral BINOL-phosphoric acids [15]. However, the reaction suffered from limited scope to aromatic aldehydes without an ortho-substitution; the

Halides as versatile anions in asymmetric anion-binding organocatalysis

• Lukas Schifferer,
• Martin Stinglhamer,
• Kirandeep Kaur and
• Olga García Macheño

Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145

• solvent-separated or solvent-shared ion pairs – in which the components have their own solvent shells –, nonpolar solvents are more likely to lead to contact-ion pairs. As such, the cation and anion are in closer proximity as one solvent shell is shared. If a chiral catalyst binds then to the anion, a

• performances as nucleophile precursors using a triazolium-amide chiral catalyst 34 [21] (Scheme 8a), as well as by Jacobsen in the desymmetrization of oxetanes 35 using TMSBr and squaramide 37 as catalyst [56] (Scheme 8b). For the latter, a more detailed mechanistic study was recently provided [57]. The

Asymmetric organocatalyzed synthesis of coumarin derivatives

• Natália M. Moreira,
• Lorena S. R. Martelli and
• Arlene G. Corrêa

Beilstein J. Org. Chem. 2021, 17, 1952–1980, doi:10.3762/bjoc.17.128

• -hydroxycoumarin (1) with the chiral catalyst 48, as shown in Scheme 15 [48]. The enantioselective synthesis of dihydrocoumarins 51 from an inverse demand [4 + 2] cycloaddition of ketenes 50 with o-quinone methides 49 using carbene catalyst (NHC) 52 was described by Ye and co-workers [49].This transformation

• this catalyst in a domino reaction of pyranocoumarins 99 [67]. The procedure proved to be efficient for obtaining products with good to excellent yields and enantiomeric excesses, and in some cases starting from three components in a one-pot procedure (Scheme 32). The chiral catalyst 100 allows the

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

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

Prins cyclization-mediated stereoselective synthesis of tetrahydropyrans and dihydropyrans: an inspection of twenty years

• Asha Budakoti,
• Pradip Kumar Mondal,
• Prachi Verma and
• Jagadish Khamrai

Beilstein J. Org. Chem. 2021, 17, 932–963, doi:10.3762/bjoc.17.77

• -stereochemistry in the major product. Asymmetric Prins cyclization Mullen and Gagné reported a first catalytic asymmetric Prins cyclization reaction between 2-allylphenol 292 and glyoxylate ester 293 using (R)-[(tolBINAP)Pt(NC6F5)2][SbF6]2 (294) as chiral catalyst [110]. An optimization study revealed that the

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

• Dimas J. P. Lima,
• Antonio E. G. Santana,
• Michael A. Birkett and
• Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

• provided aldehydes 59a and 59b (Scheme 7). The key step in this synthesis was the allylic transfer, conducted by the dropwise addition of 64 in PhCF3 at −20 °C to a mixture of 59a and 59b and the chiral catalyst S-BINOL-TiIV [OCH(CF3)2]2 providing alcohols 60a and 60b, after 12 h at −20 ºC. In addition to

Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

• Yuqing Wang,
• Gaigai Wang,
• Anatoly A. Peshkov,
• Ruwei Yao,
• Muhammad Hasan,
• Manzoor Zaman,
• Chao Liu,
• Stepan Kashtanov,
• Olga P. Pereshivko and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2020, 16, 1963–1973, doi:10.3762/bjoc.16.163

• -aldehyde-derived Ugi adducts 8 with suitable electrophiles in the presence of chiral catalyst or promotor. In this way, the peptidyl position of 8 could be simultaneously functionalized and stereodefined leading to the formation of enantioenriched products 12 (Scheme 1). Towards this goal, we have

Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands

• Shohei Mimura,
• Sho Mizushima,
• Yohei Shimizu and
• Masaya Sawamura

Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50

• systems, while the observation of a higher enantioselectivity for the (Z)-isomer substrate 1a was characteristic for the phenol–NHC chiral ligand [4][6][8]. The result suggested that the chiral catalyst may mainly discriminate the hydrogen atom and the ethoxycarbonyl group at the α-position rather than

Copper-catalyzed enantioselective conjugate addition of organometallic reagents to challenging Michael acceptors

• Delphine Pichon,
• Jennifer Morvan,
• Christophe Crévisy and
• Marc Mauduit

Beilstein J. Org. Chem. 2020, 16, 212–232, doi:10.3762/bjoc.16.24

• performed with remarkable stereoselectivity (97–99%). Furthermore, this catalytic system was easily upscalable (up to 10 g), and the chiral catalyst could be recycled without any loss of efficiency. Unfortunately, although a wide range of Grignard reagents led to excellent results, PhMgBr provided low

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• stereoselective organic electrochemical reactions along with the synthetic accomplishments achieved with these methods. Keywords: chiral auxiliary; chiral catalyst; chiral electrode; chiral electrolyte; chiral mediator; electroorganic chemistry; Introduction Electric current-assisted exchange of electrons

• intermediate 118 takes place to obtained the final compound with regeneration of chiral catalyst 114. At almost the same time, Jorgensen et al. demonstrated that the intermolecular α-arylation of aldehydes via anodic oxidation could be performed using chiral secondary amine catalyst [76]. Constant current

1,2,3-Triazolium macrocycles in supramolecular chemistry

• Mastaneh Safarnejad Shad,
• Pulikkal Veettil Santhini and
• Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

• nanoreactor because there is an acceleration of the dimerization by two orders of magnitude and the turnover of the catalyst was demonstrated. The synthesis of cyclic carbonates from epoxides and CO2 is an efficient method for CO2 fixation. The development of an effective chiral catalyst for the efficient

Dirhodium(II)-catalyzed [3 + 2] cycloaddition of N-arylaminocyclopropane with alkyne derivatives

• Wentong Liu,
• Yi Kuang,
• Zhifan Wang,
• Jin Zhu and
• Yuanhua Wang

Beilstein J. Org. Chem. 2019, 15, 542–550, doi:10.3762/bjoc.15.48

• a chiral catalyst, the obtained cycloaddition products are racemic. According to previous reports [16], after a series of arylcyclopropylamines 1 with different substituents were synthesized, the scope of 1 was then explored and the results are shown in Table 2. The data suggest that the electronic

Computational characterization of enzyme-bound thiamin diphosphate reveals a surprisingly stable tricyclic state: implications for catalysis

• Ferran Planas,
• Michael J. McLeish and
• Fahmi Himo

Beilstein J. Org. Chem. 2019, 15, 145–159, doi:10.3762/bjoc.15.15

• understanding of the kinetics and mechanism of the individual reactions. In this paper we use density functional theory calculations to systematically study the different cofactor states in terms of energies and geometries. Benzoylformate decarboxylase (BFDC), which is a well characterized chiral catalyst

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• used as catalyst. This result could be ascribed to the effect of steric hindrance on the upper rim of calix[4]arene. So, the optimization and substrate scope studies were performed by using chiral catalyst 69f and up to 98% ee was obtained (Scheme 30). In order to confirm the role of the calixarene

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• solvents. Further, they were able to improve the enantioselectivity by implying steric effects at the ortho/ortho′ (R = Et in 7) positions of the aromatics (Scheme 3) [33]. The regeneration of the catalyst was achieved by m-CPBA converting iodine compound 7′ to chiral catalyst 7. The authors predicted a

• catalyzed by a phase-transfer catalyst [74]. Their previous findings on the same reaction using a Cinchona-based phase-transfer catalyst [75] was further improved by using Maruoka’s binaphthyl-derived ammonium salt 110. The formation of intermediate 112 (chiral catalyst still attached to the substrate) from

Nucleophilic fluoroalkylation/cyclization route to fluorinated phthalides

• Masanori Inaba,
• Tatsuya Sakai,
• Shun Shinada,
• Tsuyuka Sugiishi,
• Yuta Nishina,
• Norio Shibata and
• Hideki Amii

Beilstein J. Org. Chem. 2018, 14, 182–186, doi:10.3762/bjoc.14.12

• synthesis of 1, we carried out the nucleophilic trifluoromethylation of 2 employing a small amount of chiral tertiary amines. However, the use of (1R,2R)-(N,N,N’,N’-tetramethyl)-1,2-diaminocyclohexane (8) as a chiral catalyst resulted in the formation of a racemic mixture of 1a (Table 2, entries 1 and 2

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• precursors and carry out the direct α-amination with a suitable electrophilic N-transfer reagent in the presence of a chiral catalyst to ensure an efficient face-differentiation in the C–N bond formation. This strategy has been investigated under chiral phase-transfer catalysis in the past and the results