Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• oxazolidinone-substituted ynamide also proved to undergo iodo(III)azolation in a regio- and stereoselective fashion to give the product 4ai in a moderate yield. Note that terminal alkynes such as phenylacetylene also took part in the reaction, albeit in a much-diminished yield (7% by 1H NMR; data not shown

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• more localized on the inside of the cluster for [Sc3N@Ih-C80]2−. A previous study reported that thermal treatment of La@C2v-C82 in the presence of 3-triphenylmethyl-5-oxazolidinone in toluene afforded four different benzylated La@C2v-C82 isomers [19]. Benzyl radicals may have been generated due to the

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• be envisioned for the carbonannulation of diazabicyclic alkenes with 2-formylphenylboronic acid up to the last step which likely operates through a β-hydride elimination of the Rh(I) alkoxide, furnishing the final carbonyl-containing product. In 2013, Lautens reported the synthesis of oxazolidinone

• then nucleophillically attacks the alkene in an SN2’ fashion producing the trans-isocyanate 149. Subsequently, insertion of the Rh–O bond into the isocyanate results in 150. Finally, protonolysis produces the oxazolidinone product 147e as well as regenerates the active Rh(I) catalyst. In 2013, the

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

• 31 and oxazolidinone 32 (Scheme 5) [26]. Subsequently, compound 33 was converted in four steps into aldehyde 34 which was engaged in a coupling reaction with bromoketone 35 according to Utimoto conditions to furnish the A-C-D adduct 36 as a single stereoisomer in high yield. Of note, the Utimoto

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• was synthesized by a Horner–Wadsworth–Emmons reaction of phosphonate 48 with aldehyde 47. Enantiopure aldehyde 47 was easily accessible from oxazolidinone 46 via Evans-aldol chemistry [23]. Heating of the α-ketoester 49 led to the highly substituted cyclopentanol 50 in a good dr of ≈5:1 (minor

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

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

• auxiliary yielded superior results in flow [89]. Alkylation of oxazolidinone 19 with benzyl bromide (20) in batch gave only a combined 31% yield of the benzylated products 21, with a 70% diastereomeric excess (de), accompanied by 10% decomposition to the N-benzyl derivative 22. In flow, however

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

• (Figure 2). To synthesize the regioisomeric spiro-oxazolidinone derivative 12, (1R)-(−)-myrtenol (10) was chosen as starting material (Scheme 2). The synthetic method was similar to that mentioned above for (−)-isopinocarveol. In the first step, carbamate 11 was prepared [37], then the aminohydroxylation

• ). The LAH reduction of oxazolidine 17 gave N-benzyl-N-methyl analogue 18 which, alternatively, was prepared directly from 2-oxazolidinone 9 via N-benzylation followed by LAH reduction in 2 steps. When compound 13 was reacted with phenylisothiocyanate, thiourea 20 was obtained, which underwent a

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates

• Olusesan K. Koleoso,
• Matthew Turner,
• Felix Plasser and
• Marc C. Kimber

Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165

• the γ-position [37][39][40]. An examination of the allenamide unit under these conditions is shown in Scheme 4, and the six allenylamides/sulfonamides (15, 21–25) were prepared using known conditions [52][53]. The allenamides derived from pyrrolidinone (21), piperidinone (22) and oxazolidinone (15

One-pot synthesis of oxazolidinones and five-membered cyclic carbonates from epoxides and chlorosulfonyl isocyanate: theoretical evidence for an asynchronous concerted pathway

• Esra Demir,
• Ozlem Sari,
• Yasin Çetinkaya,
• Ufuk Atmaca,
• Safiye Sağ Erdem and
• Murat Çelik

Beilstein J. Org. Chem. 2020, 16, 1805–1819, doi:10.3762/bjoc.16.148

• obtained in dichloromethane (DCM). Together with 16 known compounds, two novel oxazolidinone derivatives and two novel cyclic carbonates were synthesized with an efficient and straightforward method. Compared to the existing methods, the synthetic approach presented here provides the following distinct

• isocyanate; computational modeling; cyclic carbonates; density functional theory; oxazolidinone; Introduction Oxazolidinones (1), five-membered heterocyclic rings containing an ester group adjacent to a nitrogen atom, are important compounds in synthetic and pharmaceutical chemistry because of their

• considerable use as antibiotics [1], immunomodulators [2], antibacterials [3], as well as synthetic intermediates and chiral auxiliaries for various organic conversions [4][5][6][7]. Linezolid [1][2][3] (3) and cytoxazone [8][9] (4) are oxazolidinone derivatives having significant biological activities

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

• formation [64]. 2.2. Stereoselective benzylic fluorination of N-(2-phenylacetyl)oxazolidin-2-one using NFSI Treatment of oxazolidinone 122 with N-fluorobenzenesulfonimide (NFSI) in the presence of NaHMDS afforded the fluorinated oxazolidinone derivative 123. The reductive removal of the chiral auxiliary

• -difluorophenylalanine 115. Synthesis of β-fluorophenylalanine via 2-amino-1,3-diol derivatives. Synthesis of β-fluorophenylalanine derivatives via the oxazolidinone chiral auxiliary 122. Synthesis of β-fluorophenylalanine from pyruvate hemiketal 130. Synthesis of β-fluorophenylalanine (136) via fluorination of β

Pd-catalyzed asymmetric Suzuki–Miyaura coupling reactions for the synthesis of chiral biaryl compounds with a large steric substituent at the 2-position

• Yongsu Li,
• Bendu Pan,
• Xuefeng He,
• Wang Xia,
• Yaqi Zhang,
• Hao Liang,
• Chitreddy V. Subba Reddy,
• Rihui Cao and
• Liqin Qiu

Beilstein J. Org. Chem. 2020, 16, 966–973, doi:10.3762/bjoc.16.85

• 3d). The yield and ee value of an oxazolidinone amide were slightly lower than those of tetrahydropyrrolamide (3e, 3f). Various aromatic substituted amides were investigated. The results show that electron-rich or electron-deficient substituents on the phenyl ring have no significant influence on the

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• homolytic cleavage of the C–S bond, providing the sulfonyl radical 186. The sulfonyl radical 186 can then approach anti to the oxazolidinone moiety in 180, generating a β-sulfonyl radical 187, which, once trapped by another sulfonyl cyanide molecule 181, affords the desired product 182, and the sulfonyl

SnCl₄-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives

• Kesatebrhan Haile Asressu and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2019, 15, 2990–2999, doi:10.3762/bjoc.15.295

• disappointment, an attempted acetolysis upon changing the fucose-containing disaccharides 29 and 33 with substrate 37 did not provide the desired ring-opening product 38 albeit it bore a robust N-5/O-4-oxazolidinone-based sialyl group (Scheme 5). Furthermore, 8,9-di-O-acetylated disaccharide 39 was subjected to

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

• ) or a chiral auxiliary (i.e., oxazolidinone) into the substrate structure is required for highly stereoselective reactions [20][21][22]. ‘One-pot’ photochemical α,β-functionalization of cinnamaldehyde Over the last few years, photochemical methods for asymmetric functionalisation of carbonyl compounds

Synthesis of the polyketide section of seragamide A and related cyclodepsipeptides via Negishi cross coupling

• Jan Hendrik Lang and
• Thomas Lindel

Beilstein J. Org. Chem. 2019, 15, 577–583, doi:10.3762/bjoc.15.53

• -methylated product via oxazolidinone 24 was hampered by low yield on reaction with paraformaldehyde [47][48]. Although subsequent reduction of 24 with Et3SiH/TFA and reprotection of the free N-methyl amino acid with Boc2O proceeded smoothly and delivered iodotyrosine 25, the overall yield via 24 was not

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

• of a chiral auxiliary with lithium dibutylcuprate. Next, titanium tetrachloride-catalyzed cyanation secured another carboxy group and after a few transformations an oxazolidinone (4S,5R)-39 was obtained as a major (7:1) product readily purified chromatographically. To complete the synthesis of (2S,3R

• acid Cleavage of the 5-membered ring in the protected epoxide 88 obtained from (S)-pyroglutamic acid [93][94][95] gave the methyl ester 89 which, when adsorbed on silica gel, smoothly underwent stereospecific epoxide ring opening to give the oxazolidinone 90 (Scheme 23) [96]. Before installation of the

• compound underwent another intramolecular cyclization in the 5-exo mode to form the oxazolidinone 118. To complete the synthesis of (2S,3S,4S)-4 the secondary hydroxy group was protected as a pivalate, the hydroxymethyl fragment was oxidized after hydrolysis of the silyl ether and finally all protecting

Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand

• Anne Schnell,
• J. Alexander Willms,
• S. Nozinovic and
• Marianne Engeser

Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3

• at δ = 4.4 ppm (Figure S3, Supporting Information File 1), characteristic for an oxazolidinone (Scheme 4). In agreement with the findings from List [58] and Gschwind [46], the equilibrium concentration of the isomeric enamine is too low to be detected although this species is required as dienophile

• before, now L-proline (1 equiv) and acetone (95 equiv) were mixed first. The formation of intermediate enamine I1 and/or the isomeric oxazolidinone was validated by the detection of a signal at m/z 156 for the protonated species in ESIMS spectra, and only then the tetrazine substrate 2 (1 equiv) was

• added. By this way, it was possible to detect not only substrate 2 (m/z 237, m/z 259), product 3 (m/z 249, m/z 271, m/z 287) and the proline catalyst (m/z 116, m/z 138), but also the intermediate I1 and/or its oxazolidinone isomer (m/z 156) and the dihydropyridazine intermediate III1 (m/z 386, Figure 4

Stereodivergent approach in the protected glycal synthesis of L-vancosamine, L-saccharosamine, L-daunosamine and L-ristosamine involving a ring-closing metathesis step

• Pierre-Antoine Nocquet,
• Aurélie Macé,
• Frédéric Legros,
• Jacques Lebreton,
• Gilles Dujardin,
• Sylvain Collet,
• Arnaud Martel,
• Bertrand Carboni and
• François Carreaux

Beilstein J. Org. Chem. 2018, 14, 2949–2955, doi:10.3762/bjoc.14.274

• obtained for the desired products due to the formation of substantial amounts of ring-opened byproducts 10 resulting from the hydride addition to the carbonyl group of the oxazolidinone ring [33][34]. The alcohols 9 were then subjected to a Swern oxidation followed by a Wittig reaction to generate the

A novel and practical asymmetric synthesis of eptazocine hydrobromide

• Ruipeng Li,
• Zhenren Liu,
• Liang Chen,
• Jing Pan,
• Kuaile Lin and
• Weicheng Zhou

Beilstein J. Org. Chem. 2018, 14, 2340–2347, doi:10.3762/bjoc.14.209

• the unwanted isomer [3][4][5][6]. Other asymmetric syntheses of 1 have been reported in the literature. These relied either on organometallic catalysis [7], asymmetric tandem addition to chiral tetrahydronaphthalenes [8], bioenzymatic steps [9] or diastereoselective Evans alkylation from oxazolidinone

A stereoselective and flexible synthesis to access both enantiomers of N-acetylgalactosamine and peracetylated N-acetylidosamine

• Bettina Riedl and
• Walther Schmid

Beilstein J. Org. Chem. 2018, 14, 856–860, doi:10.3762/bjoc.14.71

• as starting material reduces the flexibility of this approach. Another strategy introduces the nitrogen at C-2 [11] via the 2-iodoxybenzoic acid-mediated generation of an oxazolidinone ring, selectively leading to C2–C3 syn-products [12]. A third approach features E-selective Julia olefination of (R

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• Reformatsky reaction between L-cysteine-derived thiazolidinic aldehyde 14 and (R)-α-chloroacetyl-2-oxazolidinone 15, leading to the corresponding β-hydroxy amide 16 in both remarkable yield (95%) and diastereoselectivity (>98% de), as shown in Scheme 6. The latter was subsequently converted into the expected

• Isobe et al. for a diastereoselective SmI2-mediated Reformatsky reaction constituting the key step of a highly economical total synthesis of prostaglandin E2 methyl ester [23]. As shown in Scheme 7, the reaction occurred between achiral aldehyde 17 and chiral oxazolidinone 18 in the presence of SmI2 in

• mediate Reformatsky reactions. As an example, chiral oxazolidinone 20 reacted with achiral aldehyde 21 in the presence of SnCl2 to afford the corresponding chiral Reformatsky product 22 as a single diastereomer (>96% de) in moderate yield (56%), as shown in Scheme 8 [24]. The latter was used to synthesize

Recent progress in the racemic and enantioselective synthesis of monofluoroalkene-based dipeptide isosteres

• Myriam Drouin and
• Jean-François Paquin

Beilstein J. Org. Chem. 2017, 13, 2637–2658, doi:10.3762/bjoc.13.262

• be achieved using an olefination reaction, a metathesis reaction or a copper-mediated reduction of 3,3-difluoropropenes. Pannecoucke’s group employed a chiral auxiliary, the Evans oxazolidinone, to prepare the non-racemic dipeptide isostere 35 (Scheme 7) [34]. Stereoselective alkoxymethylation on the

• oxazolidinone derivative 31 was first achieved with an excellent yield (88%) and diastereoselectivity (de > 95%). The chiral auxiliary was then removed and the free alcohol was oxidized to the corresponding aldehyde 32. Alkene 33 was then obtained after olefination of 32 with low selectivity ((Z):(E) = 64:36

Diastereoselective Mannich reactions of pseudo-C₂-symmetric glutarimide with activated imines

• Tatsuya Ishikawa,
• Tomoko Kawasaki-Takasuka,
• Toshio Kubota and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2017, 13, 2473–2477, doi:10.3762/bjoc.13.244

• , Nakanarusawa 4-12-1, Hitachi 316-8511, Japan 10.3762/bjoc.13.244 Abstract As an extension of the boron enolate-based aldol reactions, the oxazolidinone-installed bisimide 1a from 3-(trifluoromethyl)glutaric acid was employed for Mannich reactions with tosylated imines 2 as electrophiles to successfully obtain

• couple of routes to get successful access to such target molecules with a variety of substituents at the 2-position [1][2][3]. Previously, the oxazolidinone-installed bisimide 1a was employed for the crossed aldol reactions by the way of boron enolate which allowed the isolation of optically active

• , entry 7). Because the employment of the phenylalanine-based oxazolidinone as the chiral auxiliary under the same conditions gave similar results as the one obtained from valine (Table 1, entries 8 vs 7), we decided the conditions in entry 7 (Table 1) as the best of all tested and investigated the