Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• (Scheme 47B). The authors concluded that the new structure 186 is formed by intramolecular ring opening of the oxazolidine unit initiated by the hydroxy group either following the aldol condensation or during the reaction workup. In 2021, Zhang and Oestreich presented a Cu-catalyzed tandem conjugate

Chemistry of polyhalogenated nitrobutadienes, 17: Efficient synthesis of persubstituted chloroquinolinyl-1H-pyrazoles and evaluation of their antimalarial, anti-SARS-CoV-2, antibacterial, and cytotoxic activities

• Viktor A. Zapol’skii,
• Isabell Berneburg,
• Ursula Bilitewski,
• Melissa Dillenberger,
• Katja Becker,
• Stefan Jungwirth,
• Aditya Shekhar,
• Bastian Krueger and
• Dieter E. Kaufmann

Beilstein J. Org. Chem. 2022, 18, 524–532, doi:10.3762/bjoc.18.54

• cycle from 3-methyl-2-(2,3,3-trichloro-1-nitroallylidene)oxazolidine (6) is also described. In addition, the antimalarial activity of the synthesized compounds has been evaluated in vitro against the protozoan malaria parasite Plasmodium falciparum. Notably, the 7-chloro-4-(5-(dichloromethyl)-4-nitro-3

•  1). The predicted and found data for compounds 5a and 5b correspond well and thus support our assumptions regarding the orientation of the nucleophilic attack of 7-chloro-4-hydrazinylquinoline to nitrodienes 4. Further, we developed a new way for the formation of a pyrazole cycle from oxazolidine 6

• and a hetarylhydrazine. The oxazolidine 6 was synthetized under mild reaction conditions either from nitrodiene 1 (yield 58%) or from the benzotriazolyl derivative 2c (yield 76%). The increase in yield in case of 2c supports the suggestion that the benzotriazolyl subunit is a better leaving group

The asymmetric Henry reaction as synthetic tool for the preparation of the drugs linezolid and rivaroxaban

• Martin Vrbický,
• Karel Macek,
• Jaroslav Pochobradský,
• Jan Svoboda,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2022, 18, 438–445, doi:10.3762/bjoc.18.46

• antibiotic linezolid (1) and the anticoagulant rivaroxaban (2) – belong among modern pharmaceutics, which contain an oxazolidine-2-one moiety bearing a stereogenic center. The chirality of these drugs is a fundamental attribute for their biological activity. Herein, one of the efficient asymmetric syntheses

• syntheses of these drugs were obtained in high yields and enantiomeric excesses of up to 91% ee. Keywords: asymmetric Henry reaction; enantioselective catalysis; linezolid; oxazolidine-2-one derivatives; rivaroxaban; Introduction Oxazolidine-2-one derivatives represent an important branch of

• pharmaceutical substances [1][2][3]. This class includes for instance oxazolidine-type antibiotics [3], e.g., linezolid (1) [4] (sold under the trade name Zyvox® (Figure 1) or tedizolid [5] (sold under the trade name Sivextro®), and the anticoagulant rivaroxaban (2) [6][7] (Figure 1), a member of DOACs (direct

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• chromatography [68] (Scheme 21). Mercury(II) salts had also been successfully utilized in the cyclization of ether derivatives 61 to form stereoselectively trans-4,5-disubstituted oxazolidine derivatives 62 (Scheme 22) [69]. Later it was reported, when homologous allyloxycarbamate derivative 63 was cyclized with

• oxazolidine derivatives. Cyclization of amide derivatives induced by Hg(OAc)2. Hg(OAc)2/Hg(TFA)2-promoted cyclization of salicylamide-derived amidal auxiliary derivatives. Hg(II)-salt-mediated cyclization to form dihydrobenzopyrans. HgCl2-induced cyclization of acetylenic silyl enol ether derivatives

Stereoselective synthesis and transformation of pinane-based 2-amino-1,3-diols

• Ákos Bajtel,
• Mounir Raji,
• Matti Haukka,
• Ferenc Fülöp and
• Zsolt Szakonyi

Beilstein J. Org. Chem. 2021, 17, 983–990, doi:10.3762/bjoc.17.80

• carbamate 8 in good yield [27][28][36]. In the next step, the aminohydroxylation was accomplished by potassium osmate(VI) as the catalyst and t-BuOCl in the presence of DIPEA affording oxazolidine-2-one 9 [27]. The reaction was found to be highly stereoselective, giving exclusively the diexo-fused tricyclic

• was carried out catalyzed by potassium osmate(VI), which led to the formation of the spiro-oxazolidine-2-one 12 in a highly regio- and stereoselective manner. Based on the NMR spectroscopic measurements of the crude product, the spiro derivative 12 was obtained exclusively with the relative

• transformations of pinane-based 2-amino-1,3-diols To obtain a library of pinane-based 2-amino-1,3-diols, the oxazolidine-2-ones 9 and 12 were applied as starting materials. The alkaline hydrolysis of both 9 and 12 resulted in the same primary aminodiol 13 [38]. According to the NMR spectra and other physical and

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• initiated by an EDA complex. Mechanism of the synthesis of spirocyclic indoline derivative 47. Synthesis of cyclobutane product 50 initiated by an EDA complex. Mechanism of the synthesis of spirocyclic indoline derivative 50. Synthesis of 1,3-oxazolidine compound 59 initiated by an EDA complex. Synthesis of

Syntheses of spliceostatins and thailanstatins: a review

• William A. Donaldson

Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166

• Syntheses from ʟ-threonine-derived aldehyde Three groups utilized 4-formyl-2,2,5-trimethyl-3-oxazolidine (24) [21], derived from relatively inexpensive ʟ-threonine (<$1/g in bulk) as a chiral pool precursor for the amine stereocenter of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran fragment. In

Clickable azide-functionalized bromoarylaldehydes – synthesis and photophysical characterization

• Dominik Göbel,
• Marius Friedrich,
• Enno Lork and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2020, 16, 1683–1692, doi:10.3762/bjoc.16.139

• three-step methylation/reduction/hydrolysis sequence. Methylation of the oxazoline nitrogen afforded iminium salt 26, which was reduced to oxazolidine 27. Again, similar to 25, cyclization took place and ammonium triflate 28 was isolated in 56% yield (starting from 24). In contrast to the cyclization of

• oxazoline 24, oxazolidine 27 cyclized already during the reaction, caused by the increased basicity of the ring nitrogen. CuAAC reactions of bromocarbaldehydes We further investigated the reactivity of azide-functionalized bromocarbaldehydes 3, 4, and 5 in copper(I)-catalyzed azide–alkyne cycloaddition

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

• acylimidazole Michael acceptors, the first use of α,β-unsaturated N-acyloxazolidinones was also described in asymmetric Friedel–Crafts 1,4-additions catalyzed by chiral copper/bisoxazolidine Lewis acids [42][43][44][45][46]. Thanks to the easy post-transformation of the oxazolidine moiety, the resulting

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

• method for the enantioselective synthesis of 4,5,5-trisubstituted γ-butyrolactones 193 using an electroreductive coupling of diaryl ketones 191 with α,β-unsaturated carbonyl compounds 190 bearing chiral auxiliaries derived from imidazolidin-2-one and oxazolidine-2-ones (Scheme 60). Compound 191 underwent

Synthesis of nonracemic hydroxyglutamic acids

• Dorota G. Piotrowska,
• Iwona E. Głowacka,
• Andrzej E. Wróblewski and
• Liwia Lubowiecka

Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22

• . However, when the reaction mixture was warmed to 0 °C before quenching, an intramolecular cyclization occurred under basic conditions to give the oxazolidine (4S,5R)-25 as an almost (>20:1) pure diastereoisomer. The hydroxy group which acted as a nucleophile preferred to attack the re-face of the double

• )-2 N-Boc protection preceded the cleavage of the oxazolidine ring while silylation of the hydroxy group was necessary before oxidation of the C=C bond (Scheme 9) [58]. Further applications of the ketopinic acid framework as a chiral auxiliary relied on fine tuning of the steric environment around the

The use of 4,4,4-trifluorothreonine to stabilize extended peptide structures and mimic β-strands

• Yaochun Xu,
• Isabelle Correia,
• Tap Ha-Duong,
• Nadjib Kihal,
• Jean-Louis Soulier,
• Julia Kaffy,
• Benoît Crousse,
• Olivier Lequin and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2017, 13, 2842–2853, doi:10.3762/bjoc.13.276

• separated at this stage by column chromatography. The major diastereomer 7a was used in the following steps. Hydrolysis of the oxazolidine, followed by Jones oxidation of the alcohol 8, allowed us to recover the desired acid 9 in good yield (90%). The optical rotation of a solution of the product 9 (2S,3R

The photodecarboxylative addition of carboxylates to phthalimides as a key-step in the synthesis of biologically active 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones

• Ommid Anamimoghadam,
• Saira Mumtaz,
• Anke Nietsch,
• Gaetano Saya,
• Cherie A. Motti,
• Jun Wang,
• Peter C. Junk,
• Ashfaq Mahmood Qureshi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2017, 13, 2833–2841, doi:10.3762/bjoc.13.275

• under nitrogen purging in Pyrex flasks (cutoff: <300 nm [47]) furnished the desired addition product 3a in yields of 45 and 49% (Table 1, entries 1 and 2). The pH raised from approx. 7.5 at the beginning to about 11.5 at the end of each irradiation experiment. In both cases, the tetracyclic oxazolidine

• ca. 8.7 at the end of the irradiation. Temperature control was crucial as thermal conversion of 3a into 4 was found to occur above 40 °C. Compound 1a could be converted quantitatively to the oxazolidine derivative 4 by treatment with either sodium carbonate or potassium tert-butoxide in acetonitrile

• and protonation furnishes the observed benzylated hydroxyphthalimidine derivatives 3a–q. The nucleophilic cyclization to the oxazolidine derivative 4 may occur at different stages of the photodecarboxylation (Scheme 8). The phthalimide radical anion may undergo nucleophilic cyclization prior to C–C

Synthesis of 2-aminosuberic acid derivatives as components of some histone deacetylase inhibiting cyclic tetrapeptides

• Shital Kumar Chattopadhyay,
• Suman Sil and
• Jyoti Prasad Mukherjee

Beilstein J. Org. Chem. 2017, 13, 2153–2156, doi:10.3762/bjoc.13.214

• an overall yield of 42% over five steps. One-pot deprotection–oxidation [14] of the oxazolidine moiety in 9 proceeded uneventfully to provide N-Boc-2-amino-6-heptenoic acid (10) in good yield. The latter was smothly protected as its methyl ester using methyl iodide in the presence of cesium carbonate

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• reactions was attributed to the formation of orthoester and oxazolidine side products due to the basic reaction conditions, which were needed to neutralize the acid formed during glycosylation and to avoid the cleavage of the acid-labile benzylidene protective group. The van der Marel group further applied

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• charge on the carbon adjacent to the cyano group [76][77]. Transition-metal-catalyzed reductive decyanation Hydrogenation of α-aminonitriles The decyanation of α-aminonitriles with hydrogen present in an excess of Raney nickel was described by Husson and co-workers on oxazolidine derivatives [83][84

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

• Lucie Brulíková,
• Aidan Harrison,
• Marvin J. Miller and
• Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

• -oxazines with lower diastereoselectivities than with the corresponding cyclic counterparts, they have been successfully applied in nitroso hetero-Diels–Alder reactions. For example, the diene substituted with a pseudoephedrine-derived oxazolidine 170 gave the product in only modest stereoselectivity when

Spiro-fused carbohydrate oxazoline ligands: Synthesis and application as enantio-discrimination agents in asymmetric allylic alkylation

• Jochen Kraft,
• Martin Golkowski and
• Thomas Ziegler

Beilstein J. Org. Chem. 2016, 12, 166–171, doi:10.3762/bjoc.12.18

• -isopropylidene-β-D-psicopyranose, respectively. The latter compounds were partially deprotected under acidic conditions followed by condensation with thiocyanic acid to give an anomeric mixture of the corresponding 1,3-oxazolidine-2-thiones. The anomeric 1,3-oxazolidine-2-thiones were separated after successive

• ligands in the D-fructo- and D-psico-series via a straightforward synthetic route. The key steps in our synthesis were a Ritter type condensation reaction of partially benzyl-protected D-fructose and D-psicose derivatives with thiocyanic acid to afford the corresponding 1,3-oxazolidine-2-thiones, and the

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• of the iminium species under formation of oxazolidine or 1,3-oxazinane species 30. According to their protocol, 29 is electrolyzed under galvanostatic conditions in a divided cell, using a NaOMe/MeOH electrolyte and potassium iodide as electron transfer mediator. The method provides access to a

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

• synthesized in two steps at room temperature, first, by a nucleophilic attack of methyl hypophosphite on oxazolidine 60 followed by an intramolecular cyclization, this time without base catalyzed transesterification. The authors explained this difference of reactivity by the Thorpe–Ingold effect [38]. Indeed

• (trimethylsiloxy)phosphine. Diastereoselective ring-closing metathesis. 2-Ketophosphonate/benzene annulation. Tandem Kabachnik–Fields/transesterification reaction. Tandem Kabachnik–Fields/transesterification reaction with oxazolidine. Acknowledgements This material is based in part upon work supported by the

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

• phenylglycine derived carbamate 7c. Indeed, if the excess of Selectride was quenched with acetaldehyde after reduction of 7a, the oxazolidine 10a was obtained (under the basic reaction conditions) as the major product. The outcome of the Cbz-cleavage strongly depended on the activity of the commercial Pd/C

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

• acetic anhydride and pyridine at room temperature (Scheme 2). It should be emphasized that a mixture of dioxolanes 5 and 6 in a ratio of 7:3 is formed already in the first step [232]. The photooxygenation of oxazolidines 7a–d through the formation of hydroperoxides 8a–d gives spiro-fused oxazolidine

A unified approach to the important protein kinase inhibitor balanol and a proposed analogue

• Tapan Saha,
• Ratnava Maitra and
• Shital K. Chattopadhyay

Beilstein J. Org. Chem. 2013, 9, 2910–2915, doi:10.3762/bjoc.9.327

• preliminary report [62]. Thus, reductive amination of Garner’s aldehyde 17 (Scheme 2) with allylamine produced amine 18 which was N-protected with CbzCl to obtain 19 in an overall yield of 89% over three steps. The oxazolidine ring in compound 19 was then cleaved under acidic conditions and the resulting

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

• 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

Metathesis access to monocyclic iminocyclitol-based therapeutic agents

• Ileana Dragutan,
• Valerian Dragutan,
• Carmen Mitan,
• Hermanus C.M. Vosloo,
• Lionel Delaude and
• Albert Demonceau

Beilstein J. Org. Chem. 2011, 7, 699–716, doi:10.3762/bjoc.7.81

• (oxazolidine, cyclic ketal, etc.), or deactivated by conversion into amide or carbamate functions. Due to these protective groups even metathesis catalysts sensitive to functionalities can act efficiently under reaction conditions where an adequate balance between activity/stability factors has been met. In