Strategies for the synthesis of brevipolides

• Yudhi D. Kurniawan and
• A'liyatur Rosyidah

Beilstein J. Org. Chem. 2021, 17, 2399–2416, doi:10.3762/bjoc.17.157

• -promoted intramolecular oxacyclization. After TBS protection, intermediate 32 was collected in 86% yield from epoxide 30. Basic methanolysis of the cyclic carbonate followed by treatment with NaH and N-tosylimidazole then afforded terminal epoxide 34 in 97% yield. Unfortunately, attempts to open the

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

• toloxatone derivatives, have been reported to exhibit good affinity for human MAO-A [14]. Five-membered cyclic carbonate (1,3-dioxolan-2-one) (2) and its derivatives are valuable synthetic targets on account of several applications and pertinent properties. They are found in various natural and potential

• natural products ranging from small molecules, such as sugars, lipids and amino acids to huge molecules [56]. Computational results A detailed mechanistic investigation of the synthesis of oxazolidinone and five-membered cyclic carbonate derivatives by the reaction between epoxide 7f and CSI has been

• formation of five-membered cyclic carbonate 8f has also been investigated theoretically and it is described below (Scheme 4). A similar transition state has been proposed for the formation of 8f in the presence of CSI. The mechanism is thought to proceed by ring opening of the epoxide 7f at the 2-position

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• photoinduced cycloaddition of carbon dioxide with epoxides [56]. The synthesis of a 3D supramolecular framework, [{Mn(TCPP)0.5(H2O)}·2H2O]n, where Mn(TCPP) is Mn(II) meso-tetrakis(4-carboxyphenyl)porphyrin, was derived from MnCl2·6H2O and TCPP. The cycloaddition product, a cyclic carbonate, was obtained from

Mechanochemical synthesis of poly(trimethylene carbonate)s: an example of rate acceleration

• Sora Park and
• Jeung Gon Kim

Beilstein J. Org. Chem. 2019, 15, 963–970, doi:10.3762/bjoc.15.93

• biomedical applications [24]. The amidine base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is one of the best studied and most popular organocatalysts for ring-opening polymerizations of cyclic carbonates and lactones [25][26][27]. In contrast to the high activity of lactone polymerization, cyclic carbonate

Systematic synthetic study of four diastereomerically distinct limonene-1,2-diols and their corresponding cyclic carbonates

• Hiroshi Morikawa,
• Jun-ichi Yamaguchi,
• Shun-ichi Sugimura,
• Masato Minamoto,
• Yuuta Gorou,
• Hisatoyo Morinaga and
• Suguru Motokucho

Beilstein J. Org. Chem. 2019, 15, 130–136, doi:10.3762/bjoc.15.13

• )-limonene-derived diol and its corresponding five-membered cyclic carbonate were prepared. The diol (cyclic carbonate) comprises four diastereomers based on the stereochemical configuration of the diol (and cyclic carbonate) moiety. By choosing the appropriate starting compounds (trans- and cis-limonene

• their characteristic signals. Keywords: cyclic carbonate; diastereomer; diol; limonene; NMR; Introduction (R)-Limonene (LM) is a naturally occurring terpene, and therefore a very attractive and renewable resource [1]. Its derivatives have versatilely and widely been studied [1][2][3][4]. Otherwise

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

• Maurizio Selva,
• Alvise Perosa,
• Sandro Guidi and
• Lisa Cattelan

Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181

• for dimethyl carbonate production: Ionic liquid-based catalysts brought about a number of improvements for the synthesis of DMC. As mentioned above, the synthesis of DMC through CO2 insertion into an epoxide and the subsequent transesterification of the formed cyclic carbonate with methanol represent

Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC)

• Helmut Ritter,
• Monir Tabatabai and
• Markus Herrmann

Beilstein J. Org. Chem. 2016, 12, 245–252, doi:10.3762/bjoc.12.26

• chromatography and the 1H NMR spectra of 3a and 3b are shown in Figure 2 and Figure 3. After dissolving monomers 3a and 3b in a polar solvent, they show the above mentioned self-cleaving process yielding the corresponding amine hydrobromide (4a,b) and the cyclic carbonate 4,4-dimethyl-1,3-dioxolan-2-one (5). As

• coupled with cyclization to create the cyclic carbonate 5, the homopolymer could be self-deactivated due to competing hydrogen-bond interactions of the urethane carbonyl group with neighboring groups. Since the comonomer should act as diluting agent a better access of the carbonyl group to the bromo

Robust bifunctional aluminium–salen catalysts for the preparation of cyclic carbonates from carbon dioxide and epoxides

• Yuri A. Rulev,
• Zalina Gugkaeva,
• Victor I. Maleev,
• Michael North and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2015, 11, 1614–1623, doi:10.3762/bjoc.11.176

• mixture and reused. Keywords: aluminium; carbon dioxide; cyclic carbonate; epoxide; salen; Introduction Carbon dioxide is a renewable and inexpensive carbon source, so great efforts have been directed at developing novel methods for the valorization of this abundant raw material [1]. One way of

• capability (via the anion in the case of catalysts containing ammonium salts), with a concomitant increase in their activity [12][13]. Recently, more environmentally benign aluminium-based complexes, including salen complexes, have been introduced to catalyse cyclic carbonate production [14]. The performance

• % conversion of styrene oxide to the corresponding cyclic carbonate after 24 hours, whereas complex 1 gave only 47% conversion under the same conditions (Table 1, entries 4 and 12). Increasing either the temperature of the reaction or the carbon dioxide pressure had positive effects on the catalytic

Surprisingly facile CO₂ insertion into cobalt alkoxide bonds: A theoretical investigation

• Willem K. Offermans,
• Claudia Bizzarri,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 1340–1351, doi:10.3762/bjoc.11.144

• CO2, catalysed by LiBr [41]. The preferred pathways principally involve ring opening of the epoxide, followed by CO2 insertion and ring closure of the cyclic carbonate. Interestingly, in the Re(I)-catalysed reaction (b), an alternative reaction pathway was followed, whereby the first step is CO2

Anion effect controlling the selectivity in the zinc-catalysed copolymerisation of CO₂ and cyclohexene oxide

• Sait Elmas,
• Muhammad Afzal Subhani,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 42–49, doi:10.3762/bjoc.11.7

• ], for which an active site comprising two Lewis acidic zinc centres in vicinity had been proposed [29]. Three catalytic cycles, copolymerisation, homopolymerisation and formation of cyclic carbonate are closely linked (Scheme 4) [28]. The reaction is initiated by coordination of an alcoholate to one of

• closes the homopolymerisation cycle. The cyclic carbonate is formed by backbiting of a terminal alcoholate, when the chain becomes released after preceding insertion of CO2. Chains, which dissociate from the surface of the catalyst, restart a catalytic cycle when they re-attach to a free zinc site or

Comparing kinetic profiles between bifunctional and binary type of Zn(salen)-based catalysts for organic carbonate formation

• Carmen Martín and
• Arjan W. Kleij

Beilstein J. Org. Chem. 2014, 10, 1817–1825, doi:10.3762/bjoc.10.191

• Scheme 2 first the epoxide coordinates to the Zn center allowing Lewis acid activation following the ring opening by nucleophilic attack of X. Then, carbon dioxide insertion into the metal–oxygen bond takes place and a consecutive cyclisation step (ring closure) occurs to give the cyclic carbonate and

• anchored onto the ligand framework are less active than “similar” binary-type catalysts based on comparable components. For instance, coupling between 1,2-epoxyhexane and CO2 to afford the cyclic carbonate derivative mediated by binary Zn(salphen) 1/NBu4I was virtually complete whereas the alkylated Zn

• experimental section). As benchmark substrate 1,2-epoxyhexane was chosen, and in all studied cases complete selectivity towards the cyclic carbonate was observed under neat conditions. The conversion of the substrate was calculated by 1H NMR spectroscopy of an aliquot taken from the reaction mixture at the

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• substituted hydroisoindolone moiety fused to a macrocyclic ring (ring size 9–14). In certain cases, the ring system can be oxidized to an unusual cyclic carbonate as observed for cytochalasin E (53). Depending on the amino acid incorporated in the isoindolone moiety, the cytochalasans can be further

Photoreactions of cyclic sulfite esters: Evidence for diradical intermediates

• Rick C. White,
• Benny E. Arney Jr. and
• Heiko Ihmels

Beilstein J. Org. Chem. 2012, 8, 1208–1212, doi:10.3762/bjoc.8.134

• of cyclic carbonate esters such as 1b, as evidenced by the interception with appropriate trapping reagents; whereas the formation of persistent primary photoproducts has not been observed [13]. In contrast, we have found that under significantly milder photochemical conditions (3 h versus 15 h), the

• irradiation of the cyclic sulfite 8 for 3 h in acetonitrile gave phenyl acetaldehyde (3a), bibenzyl (4) and toluene (7) in Scheme 2; however, in contrast to the results of the photoreaction of the cyclic carbonate ester 1a under similar conditions, the oxirane 2a was not detected as a reaction product. The

• products with the methyl groups of the standard. Mass spectrometric data were recorded on photolysates immediately after reactions. Photolysis of cyclic carbonate esters 1a and 1b in acetonitrile. Photoreactivity of styrene glycol sulfite (8). Photochemical pathway for photoextrusion of SO2 from cyclic

Aldol elaboration of 4,5,6,7-tetrahydroisoxazolo[4,3-c]pyridin-4-ones, masked precursors to acylpyridones

• Raymond C. F. Jones,
• Abdul K. Choudhury,
• James N. Iley,
• Mark E. Light,
• Georgia Loizou and
• Terence A. Pillainayagam

Beilstein J. Org. Chem. 2012, 8, 308–312, doi:10.3762/bjoc.8.33

• 13, (LiAlH4, THF) to give the 1,3-diol 14 in 75% yield. This was followed by synthesis of the cyclic carbonate 15 by treating the 1,3-diol 14 with methyl chloroformate (Et3N, CH2Cl2; 74%). In the final step, carbonate 15 was treated with palladium dibenzylideneacetone in dry MeCN at room temperature

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• , treatment of propargylic tert-butyl carbonate 114 with 1 mol % PPh3AuNTf2 in CH2Cl2 at room temperature led to isolation of the cyclic carbonate in 83% yield. Syntheses of oxetan-3-ones typically demand multiple synthetic steps and/or highly functionalized substrates. Alternatively, Ye et al. [54] developed