Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• , was not ruled out. In 2013, Nevado and co-workers used (R,R)- and (S,S)-tert-butyl lactate iodotoluene difluoride (8) for the aminofluorination of alkenes toward the synthesis of enantiomerically pure β-fluorinated piperidines 6 (Scheme 3) [28]. A range of enantiomerically pure fluorinated piperidines

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

Electrochemical formal homocoupling of sec-alcohols

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masashi Shiota,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2022, 18, 1062–1069, doi:10.3762/bjoc.18.108

• anode-free electrochemical protocol for the synthesis of pinacol-type vic-1,2-diols from sec-alcohols, namely benzyl alcohol derivatives and ethyl lactate. The corresponding vic-1,2-diols are obtained in moderate to good yields, and good to high levels of stereoselectivity are observed for sec-benzyl

• substrate 1k gave 2k in a less satisfactory yield but with good diastereoselectivity. 1-Phenyl-1-propanol (1l) was successfully transformed into the desired product 2l in a moderate yield. In addition, ethyl lactate (1m) provided the corresponding vic-1,2-diol 2m in 60% yield but with low

Preparation of mono-substituted malonic acid half oxyesters (SMAHOs)

• Tania Xavier,
• Sylvie Condon,
• Christophe Pichon,
• Erwan Le Gall and
• Marc Presset

Beilstein J. Org. Chem. 2021, 17, 2085–2094, doi:10.3762/bjoc.17.135

• such as citronellol (4ja, 58%) and (−)-ethyl lactate (4ka, 32%) could also be employed for the direct preparation of elaborated reagents. Conclusion We have prepared more than 30 SMAHOs including numerous new compounds using different strategies, thus adding a consequent input to the knowledge of these

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• the better nucleophilicity. Indeed, a methyl lactate (Me-La) and ethyl lactate yield of 70% and 21% was obtained, respectively, using soluble zinc acetate at reflux temperature [264]. Interestingly, under the same reaction conditions, PET was unreactive, thus enabling the selectively recycle of mixed

• PET/PLA plastic waste. It was suggested that the different reactivity between PLA and PET is attributable to the amorphous, less rigid structure of PLA and to the potential of forming five-membered chetate ring intermediates between Zn(II) ions and lactate units, which favour the transesterification

Synthetic strategies of phosphonodepsipeptides

• Jiaxi Xu

Beilstein J. Org. Chem. 2021, 17, 461–484, doi:10.3762/bjoc.17.41

• phosphonodepsipeptides as inhibitors of carboxypeptidase A (Scheme 2) [20]. VanX is a Zn(II)-dependent ᴅ-Ala-ᴅ-Ala dipeptidase. To prepare novel inhibitors of VanX, N-[(1-aminoethyl)hydroxyphosphinyl]-ᴅ-lactate (20a), and {S-[(aminoethyl)hydroxyphosphinyl]thio}acetic acid (20b) were synthesized via coupling of the

• methyl N-Cbz-protected 1-aminoethylphosphonochloridate 13b with methyl ᴅ-lactate (22a) and methyl mercaptoacetate (22b), respectively, followed by a basic hydrolysis and hydrogenolysis. The bioassay results indicated that the phosphonothiodepsidipeptide 20b did not inhibit VanX (Scheme 3) [21]. It was

• reacted with benzyl (R)-lactate ((R)-26b) or benzyl (R)-2-phenyllactate ((R)-26f). The optically active phosphonodepsidipeptides 28 were obtained after hydrogenolysis and tested for their biological activity (Scheme 5) [22]. The phosphonodepsidipeptides 31 were synthesized by the esterification of N-Cbz

Syntheses of spliceostatins and thailanstatins: a review

• William A. Donaldson

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

• asymmetric synthesis of a (Z)-2-hydroxy-3-pentene unit, with most proceeding via the cis-reduction of 4-acetoxy-2-pentynoic acid (13). The synthesis by Kitahara et al. [8][9] is the exception, where the chiral center is derived from relatively inexpensive (S)-ethyl lactate (14). This was transformed into the

Design, synthesis and application of carbazole macrocycles in anion sensors

• Alo Rüütel,
• Ville Yrjänä,
• Sandip A. Kadam,
• Indrek Saar,
• Mihkel Ilisson,
• Astrid Darnell,
• Kristjan Haav,
• Tõiv Haljasorg,
• Lauri Toom,
• Johan Bobacka and
• Ivo Leito

Beilstein J. Org. Chem. 2020, 16, 1901–1914, doi:10.3762/bjoc.16.157

• , starting with formate. MC008 was able to fit acetate and lactate. Thus, an additional binding site was available for lactate. In the complexes of lactate with MC006–MC009, a hydrogen bond was present between the oxygen of the hydroxy group of lactate and the NH group of the macrocyclic amide. See Figure 5

• for visualization. An equilibrium likely existed between two conformers where one complex had an additional hydrogen bond and the other included intramolecularly bonded lactate. For the lactate complexes with the larger receptors, whether one dominant conformer or a mixture of two conformers was

• for MC002 with lactate and pivalate were obtained by UV–vis measurements as absolute values [31]. Five carboxylates were studied in the form of their tetrabutylammonium salts: pivalate, acetate, benzoate, lactate, and formate. The anions were titrated in DMSO-d6/H2O solvent systems of two proportions

Suzuki–Miyaura cross coupling is not an informative reaction to demonstrate the performance of new solvents

• James Sherwood

Beilstein J. Org. Chem. 2020, 16, 1001–1005, doi:10.3762/bjoc.16.89

• conventional solvents. In this work, the suitability of the Suzuki–Miyaura reaction to demonstrate the usefulness of new solvents was evaluated, including Cyrene™, dimethyl isosorbide, ethyl lactate, 2-methyltetrahydrofuran (2-MeTHF), propylene carbonate, and γ-valerolactone (GVL). It was found that the cross

• lactate [10], 2-methyltetrahydrofuran (2-MeTHF) [11], γ-valerolactone (GVL) [12], dimethyl isosorbide (DMI) [6], and propylene carbonate [7]. This study compares solvents under the same conditions to offer a fair comparison. Additional solvents were included to ensure a range of polarities were

Why do thioureas and squaramides slow down the Ireland–Claisen rearrangement?

• Dominika Krištofíková,
• Juraj Filo,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2019, 15, 2948–2957, doi:10.3762/bjoc.15.290

• was isolated in 58% when the reaction was carried out in dimethyl ethylene glycol (Table 5, entry 6). However, Ireland–Claisen rearrangement of ester 1c did not proceed in 2,2,2-trifluoroethanol, ethyl ʟ-lactate or in 2-butanone. Interestingly, the best yield of acid 3c (95%) was obtained when the

α,ß-Didehydrosuberoylanilide hydroxamic acid (DDSAHA) as precursor and possible analogue of the anticancer drug SAHA

• Shital K. Chattopadhyay,
• Subhankar Ghosh,
• Sarita Sarkar and
• Kakali Bhadra

Beilstein J. Org. Chem. 2019, 15, 2524–2533, doi:10.3762/bjoc.15.245

• clearly the truncated analogue 11g is less effective. Loss of cell viability by LDH assay LDH assays quantitatively measures lactate dehydrogenase (LDH) released into the media from damaged cells as a biomarker for cellular cytotoxicity [35][36]. Hence, to further characterize compound-induced HeLa cell

• . Loss of cell viability by LDH assay LDH assays quantitatively measures lactate dehydrogenase (LDH) released into the media from damaged cells as a biomarker for cellular cytotoxicity [35][36]. LDH or lactate dehydrogenase activity was measured quantitatively for both control and most active 11b treated

Tuning the stability of alkoxyisopropyl protection groups

• Zehong Liang,
• Henna Koivikko,
• Mikko Oivanen and
• Petri Heinonen

Beilstein J. Org. Chem. 2019, 15, 746–751, doi:10.3762/bjoc.15.70

• protection Two general routes have been reported for the preparation of 1b–e [6][8]. The 2-benzyloxypropene (1b) was synthesized starting from methyl lactate, which was deprotonated and then alkylated with benzyl bromide. Hydrolysis, reduction and elimination yielded 1b [6]. A shorter route starts from

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

• 10.3762/bjoc.14.274 Abstract In this paper, a new access to several chiral 3-aminoglycals as potential precursors for glycosylated natural products is reported from a common starting material, (−)-methyl-L-lactate. The stereodivergent strategy is based on the implementation of a ring-closing metathesis of

• diastereoisomer, the carbamate-protected 3-aminoglycal of L-saccharosamine 2, employing the (S)-(−)-methyl lactate as common starting material. The efficiency and generality of this methodology was also demonstrated by a new synthesis of C-3 unbranched amino glycals, L-daunosamine 3 and L-ristosamine 4

• depending on the absolute configuration of the chiral auxiliary used. The aldehyde 5 was first prepared according to a described procedure in two steps from methyl L-lactate (Scheme 1) [31]. The reaction with (R)- or (S)-oxazolidinones 6 led to the formation of 2,3-syn aldol products 7 in good yields with a

Assessing the possibilities of designing a unified multistep continuous flow synthesis platform

• Mrityunjay K. Sharma,
• Roopashri B. Acharya,
• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2018, 14, 1917–1936, doi:10.3762/bjoc.14.166

• ) condensation b) aromatic nucleophilic substitution reaction, c) deprotection and d) formation of lactate salt. Details of the same are given below: Condensation: Condensation takes place in a first reactor TR1 between the nitrile and hydrazine at high temperature and under pressure. Here, the nitrile was

• separator enters into the tubular reactor TR3 at a temperature of 20–40 °C with a residence time of 4 hours. Into this reactor nitrogen gas was pumped through peristaltic pump P7 and formic acid using pump P8. In TR3 gas–liquid reaction takes place. Formation of the lactate salt: In step four, lactic acid

• was pumped through pump P3 to form the final lactate salt of the product. Here the excess of formic acid and lactic acid was removed by the rotary evaporator RE1, then passes through TR4 into the crystallization tank CT1. The solid product formed was filtered in F1 and stored in a tank T1. Challenges

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• derivative 42f, due to the Lewis basicity of the nitro group. These stereochemical outcomes were also observed in the reaction of acrylamides by means of anchimeric assistance. Preliminary studies to identify asymmetric variants indicated that, in the presence of lactate-based chiral iodoarene catalyst 43

• diastereoselective catalytic fluorination was developed by the same group (Scheme 14, bottom) [65] using the lactate-based resorcinol derivative 44 as the catalyst. By this route chiral 4-fluoroisochromanones 46 could be accomplished in high enantio- and diastereoselectivity. The same I(III) intermediate 47 was

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

• class of C2-symmetric chiral iodoarene precatalyst 8a using (−)-ethyl lactate as a chiral linker with the aromatics attached followed by its successful conversion to the amide derivative to generate precatalyst 8a [37][38]. Application of this precatalyst 8a was employed for the Kita oxidation [32] with

• -symmetric reagent 9a to obtain a C2-symmetric chiral iodoarene reagent 9b having an ester end group instead of an amide (as in case of Ishihara’s work). The enantioselective oxylactonization was achieved efficiently using stoichiometric amounts of chiral reagent 9b (Scheme 9). This lactate-derived I(III

• oxy/amino group followed by the nucleophilic addition of the aryl group delivers the desired products 54. The key to success also lies on the enantiotopic face discrimination of the alkene by the lactate-based chiral iodine reagent. This difunctionalization strategy was further showcased by Muñiz et

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

• Eirinaios I. Vrettos,
• Gábor Mező and
• Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

• Heinrich Warburg in the early 1900s, who was awarded the Nobel Prize in 1931. He proposed that malignant tumor growth relies on aerobic glycolysis, in contrast to normal cells that generate energy by mitochondrial oxidative phosphorylation. The fact that cells converted pyruvate to lactate, even in the

Enantioselective dioxytosylation of styrenes using lactate-based chiral hypervalent iodine(III)

• Morifumi Fujita,
• Koki Miura and
• Takashi Sugimura

Beilstein J. Org. Chem. 2018, 14, 659–663, doi:10.3762/bjoc.14.53

• iodine reagents using a lactate motif has been employed for several types of oxidation reaction since we first reported this procedure [18]. Enantioselective oxidative transformations include the dearomatization of phenols [19][20][21][22][23][24], α-functionalization of carbonyl compounds [25][26][27

• ][28][29], and vicinal difunctionalization of alkenes [18][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. Here, the efficiency of the lactate-based chiral hypervalent iodine reagents 4a–e (Figure 1) was assessed using the dioxytosylation of styrenes as a reference

• reaction. A series of lactate-derived aryl-λ3-iodanes 4a–e was used for the oxidation of styrenes 1 in the presence of p-toluenesulfonic acid (TsOH) in dichloromethane. The reaction proceeded at −50 °C to give the 1,2-dioxytosylated product 3 and the rearranged product 5. The yields of 3 and 5 were

Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review

• Fabio Tonin and
• Isabel W. C. E. Arends

Beilstein J. Org. Chem. 2018, 14, 470–483, doi:10.3762/bjoc.14.33

• an immobilized NAD+-dependent 7α-HSHS (first reactor column); afterwards, 7-oxo-LCA is reduced to UDCA by an immobilized NADP+-dependent 7β-HSDH (second reactor column). The cofactors are individually regenerated in each column by the co-immobilized enzymes, lactate dehydrogenase (LDH) and glucose

• most used enzymes for the cofactor regeneration are glucose dehydrogenase (glucose to glucuronic acid), lactate dehydrogenase (pyruvate to lactate), glutamate dehydrogenase (α-ketoglutarate to glutamate) and formate dehydrogenase (formate to CO2). In particular, the last enzyme is interesting because

• , ursocholic acid; UDCA, ursodeoxycholic acid; HSDH, hydroxysteroid dehydrogenase; LDH, lactate dehydrogenase; GDH, glucose dehydrogenase. Chemical structure of UDCA. Chemical structures of bile acids and salts. Comparison between Wolff–Kishner and Mozingo reduction. Notably the overall chemical reaction is

Transition-metal-free synthesis of 3-sulfenylated chromones via KIO₃-catalyzed radical C(sp²)–H sulfenylation

• Yanhui Guo,
• Shanshan Zhong,
• Li Wei and
• Jie-Ping Wan

Beilstein J. Org. Chem. 2017, 13, 2017–2022, doi:10.3762/bjoc.13.199

• as KI, I2 or KIO3 could all catalyze the domino reaction to provide product 3a, wherein KIO3 displayed the highest catalytic activity (entries 2–4, Table 1). On the other hand, in the reactions performed in different media, including DMSO, ethyl lactate (EL), EtOH, MeCN, 1,4-dioxane and toluene, DMF

Total syntheses of the archazolids: an emerging class of novel anticancer drugs

• Stephan Scheeff and
• Dirk Menche

Beilstein J. Org. Chem. 2017, 13, 1085–1098, doi:10.3762/bjoc.13.108

• a boron-mediated anti-aldol reaction [67] of lactate-derived ethyl ketone 13 with aldehyde 12, which in turn was available from aldehyde 9 by HWE olefination. This Paterson aldol reaction and related aldol reactions, which have been amply used by the Menche group [68][69][70], proceeded with

Cyclodextrins tethered with oligolactides – green synthesis and structural assessment

• Cristian Peptu,
• Mihaela Balan-Porcarasu,
• Alena Šišková,
• Ľudovít Škultéty and
• Jaroslav Mosnáček

Beilstein J. Org. Chem. 2017, 13, 779–792, doi:10.3762/bjoc.13.77

• structural assignment was performed for the respective m/z values using the following equation: m/z = 1134 (β-CD) + n * 144 (LA) + 39 (K). The main peaks of the considered series were adducts of K+, but adducts with Na+ were also identified (Δm/z = −16). Considering the lactate (72 Da) as a monomer unit, the

• chromatogram and Figure S9 (Supporting Information File 1) – MALDI–MS spectrum) contained only PLA oligomers having from 16 to 28 lactate monomer units. However, all fractions from f3 to f7 may contain PLA homopolymers which are co-eluted with the CD-LA product (vide infra LC–ESI–MS characterization). The LC

• number of lactate monomer units. These species could be formed as a result of transesterification reactions (intra- or intermolecular), which may occur in the melt reaction system. The presence of PLA homopolymers was also observed, their corresponding m/z being calculated by the following equation: m/z

Supercritical carbon dioxide: a solvent like no other

• Jocelyn Peach and
• Julian Eastoe

Beilstein J. Org. Chem. 2014, 10, 1878–1895, doi:10.3762/bjoc.10.196

•  9). Ionic liquids solubilised included 1,1,3,3-tetramethylguanidinium acetate (TMGA, compound 46, Figure 9), 1,1,3,3-tetramethylguanidinium lactate (TMGL, compound 47, Figure 9) and 1,1,3,3-tetramethylguanidinium trifluoroacetate (TMGT, compound 48, Figure 9). Additives such as methyl orange, CoCl2

Olefin cross metathesis based de novo synthesis of a partially protected L-amicetose and a fully protected L-cinerulose derivative

• Bernd Schmidt and
• Sylvia Hauke

Beilstein J. Org. Chem. 2014, 10, 1023–1031, doi:10.3762/bjoc.10.102

• Bernd Schmidt Sylvia Hauke Institut für Chemie, Organische Synthesechemie, Universität Potsdam, Karl-Liebknecht-Straße 24–25, 14476 Potsdam-Golm, Germany 10.3762/bjoc.10.102 Abstract Cross metathesis of a lactate derived allylic alcohol and acrolein is the entry point to a de novo synthesis of 4

• -benzoate protected L-amicetose and a cinerulose derivative protected at C5 and C1. Keywords: carbohydrates; de novo synthesis; lactate; metathesis; ruthenium; Introduction Many drugs and bioactive natural products are glycoconjugates, which contain an aglycon part linked through glycosidic bonds to one

• ], respectively, which both use enantiomerically pure L-ethyl lactate (1) as the starting material (Scheme 1). The synthetic routes rely on the highly diastereoselective two-step conversion of ethyl lactate to allylic alcohol 2 [36][37] and further to the RCM precursor 3, which then undergoes RCM-isomerization to

Unusual polymorphism in new bent-shaped liquid crystals based on biphenyl as a central molecular core

• Anna Kovářová,
• Svatopluk Světlík,
• Václav Kozmík,
• Jiří Svoboda,
• Vladimíra Novotná,
• Damian Pociecha,
• Ewa Gorecka and
• Natalia Podoliak

Beilstein J. Org. Chem. 2014, 10, 794–807, doi:10.3762/bjoc.10.75

• formation of mesophases, and the introduction of a chiral lactate terminal chain destabilizes mesophases for the first type of mutual orientation of ester groups, attached to the central core. On the contrary, for the opposite orientation of esters, the terminal chain has no effect on the mesomorphic

• materials of series III, the columnar B1Rev phase appears for IIIa and the sequence SmAP-B1Rev was found in compound IIIb. The materials IIc and IIIc possessing the chiral lactate unit in the terminal chain were not mesogenic. In series IV–VI the orientation of the ester group attached to the biphenyl unit

• polyfluoroalkyl terminal chain supports formation of mesophases, introduction of a chiral lactate terminal chain destabilizes the mesogenic behavior (IIc and IIIc do not exhibit mesophases). For all compounds of series IV–VI, the B1Rev-type phases were observed and the terminal chain does not play an important