Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

• Svetlana V. Amosova,
• Andrey A. Filippov,
• Nataliya A. Makhaeva,
• Alexander I. Albanov and
• Vladimir A. Potapov

Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47

• proceeding at the C2 carbon atom of the seleniranium cation 2 with dithiocarbomates [31], thiourea [32], alcohols [42], functionalized organic acids [43][44], functionalized pyridines [45], ammonium thiocyanate [46], and mercapto benzazoles [40] were developed (Scheme 4). The new methodology of a

KOt-Bu-promoted selective ring-opening N-alkylation of 2-oxazolines to access 2-aminoethyl acetates and N-substituted thiazolidinones

• Qiao Lin,
• Shiling Zhang and
• Bin Li

Beilstein J. Org. Chem. 2020, 16, 492–501, doi:10.3762/bjoc.16.44

• coordination chemistry, and also valuable protecting or directing groups in catalysis [1][2][3]. 2-Oxazolines are a readily stable class of heterocycles resistant to a range of nucleophiles, bases, or radicals [4][5], which can be easily generated from amino alcohols and carboxylic acids, and from alkenes or

• investigated, and 88% yield of 2-(dibenzylamino)ethanol (6) was successfully produced in the presence of 2.0 equiv of K2CO3 in MeOH at room temperature for 24 h (Scheme 6). This result indicated that these types of 2-aminoethyl acetate products are useful building blocks for functionalized alcohols. Next, to

Recent advances in photocatalyzed reactions using well-defined copper(I) complexes

• Mingbing Zhong,
• Xavier Pannecoucke,
• Philippe Jubault and
• Thomas Poisson

Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42

• )(xantphos)]BF4 as the catalyst and DABCO as the base (Scheme 27). The products were obtained in moderate to good yields and moderate diastereoselectivities. The reaction was applied to N-alkoxyphthalimides derived from aliphatic and benzyl alcohols and heteroaromatic ones. To explain the reaction outcome

• amination of NHP esters. Photocatalytic decarboxylative alkynylation using [Cu(I)(dq)(binap)]BF4. Copper-photocatalyzed alkylation of glycine esters. Copper-photocatalyzed borylation of organic halides. aUnder continuous flow conditions. Copper-photocatalyzed α-functionalization of alcohols with glycine

• ester derivatives. δ-Functionalization of alcohols using [Cu(I)(dmp)(xantphos)]BF4. Photocatalytic synthesis of [5]helicene and phenanthrene. Oxidative carbazole synthesis using in situ-formed [Cu(I)(dmp)(xantphos)]BF4. Copper-photocatalyzed functionalization of N-aryl tetrahydroisoquinolines. Bicyclic

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• and mono-N-methylated spiro 1,3-amino alcohols 124. The mixture was equilibrated under reflux allowing P-center inversion and an uneven mixture of diastereoisomers 125 and 127 was obtained. Treating the mixture with borane·dimethyl sulfide gave a mixture of diastereoisomers in a ratio of 2:5. The

• carbon dioxide and phenyllithium gives the phosphine ferrocene carboxylic acid 152 as the major reagent. Oxidation of the phosphine using hydrogen peroxide generated the phosphine oxide 153. In situ chlorination of the carboxylic acid followed by addition of the chiral amino alcohols gave the phosphoryl

• amido alcohols 154. Cyclization in the presence of tosyl chloride/triethylamine yielded the analogous ferrocenyl phosphoryl oxazoles 155, which were further reduced to give the corresponding phosphine oxazole ligands 156. The ferrocenylphosphine oxazole ligand 156 is a fascinating example which contains

Ultrasonic-assisted unusual four-component synthesis of 7-azolylamino-4,5,6,7-tetrahydroazolo[1,5-a]pyrimidines

• Yana I. Sakhno,
• Maryna V. Murlykina,
• Oleksandr I. Zbruyev,
• Anton V. Kozyryev,
• Svetlana V. Shishkina,
• Dmytro Sysoiev,
• Vladimir I. Musatov,
• Sergey M. Desenko and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2020, 16, 281–289, doi:10.3762/bjoc.16.27

• applying different temperatures in the range of 0–110 °C (both with the help of conventional heating and microwave irradiation) and by using different solvents and catalysts, such as HOAc, DMSO, primary alcohols with and without the presence of HCl, Yb(OTf)3, or Et3N. In all these cases, mixtures of

Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation

• Jucleiton J. R. Freitas,
• Queila P. S. B. Freitas,
• Silvia R. C. P. Andrade,
• Juliano C. R. Freitas,
• Roberta A. Oliveira and
• Paulo H. Menezes

Beilstein J. Org. Chem. 2020, 16, 168–174, doi:10.3762/bjoc.16.19

• organometallics in solution resulting in mixtures of the two reagents [15]. Thus, upon reaction with an aldehyde, mixtures of propargylic and allenic alcohols can be obtained through a chelate transition state (SE2'). Attempts to improve the regioselectivity of the propargylation reaction by using allenic

• conversion of aldehydes into the corresponding homopropargylic alcohols 2 in moderate to high yields and in a very regioselective way, while the propargylated product was obtained as the major product in all cases. Aromatic aldehydes such as benzaldehyde, 2-methylbenzaldehyde and 3,5-dimethylbenzaldehyde

• products 2e–h were obtained in good yields and regioselectivities. In the same way, aldehydes containing electron-withdrawing groups such as the nitro group also reacted without influence of the substituent location to give the corresponding homopropargylic alcohols 2m and 2n in good yields. It is

The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates

• Narasimhamurthy Rajeev,
• Toreshettahally R. Swaroop,
• Ahmad I. Alrawashdeh,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Seegehalli M. Anil,
• Kuppalli R. Kiran,
• Chandra,
• Paris E. Georghiou,
• Kanchugarakoppal S. Rangappa and
• Maralinganadoddi P. Sadashiva

Beilstein J. Org. Chem. 2020, 16, 159–167, doi:10.3762/bjoc.16.18

• methods for carbamothioates have been reported. These include reactions of chlorothioformates with amines [14], thiocarbonyl benzotriazoles with alcohols [15], copper-catalyzed reactions of α-substituted stannanes with carbamothioates [16], reactions of isothiocyanates with alcohols [6][17], and reactions

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

• Katarzyna Włodarczyk,
• Piotr Borowski and
• Marek Stankevič

Beilstein J. Org. Chem. 2020, 16, 88–105, doi:10.3762/bjoc.16.11

• 2 and 3). The difference must therefore have arisen from the different C–O bond dissociation energies of the alcohols and mesylates. Assuming that the Lewis acid coordinated to either hydroxy oxygen atom or to one of the oxygen atoms of the mesyl group, the activation energies for C–O bond

• on the structure of the initial alcohol, the acid used (Brønsted or Lewis), and the reaction conditions (temperature, time), the acid-promoted transformations of the alcohols may lead to two different products: β- or γ-mercaptoalkylphosphine oxides. The formation of γ-mercaptoalkylphosphine oxides

Microwave-assisted synthesis of 2-substituted 4,5,6,7-tetrahydro-1,3-thiazepines from 4-aminobutanol

• María C. Mollo,
• Natalia B. Kilimciler,
• Juan A. Bisceglia and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2020, 16, 32–38, doi:10.3762/bjoc.16.5

• alcohols promoted by trimethylsilyl polyphosphate (PPSE) in solvent-free conditions allowed for the synthesis of several hitherto unreported seven-membered iminothioethers bearing 2-aryl, alkenyl, aralkyl and alkyl substituents. The cyclodehydration reaction is likely to involve an SN2-type displacement

• heterocycles [48][49][50][51][52][53][54], we developed a general method for the preparation of five- and six-membered cyclic iminoethers (2-oxazolines and 5,6-dihydro-4H-1,3-oxazines, respectively), by MW-assisted ring closure of amido alcohols promoted by PPA esters [54]. PPE and PPSE were then tested for

• thionation of the corresponding 4-amido alcohols cannot be used, as the OH is almost as reactive as the amide carbonyl toward Lawesson's reagent, the most commonly used thionating agent [56]. Two syntheses of ω-thioamidobutanols were recently reported by Nguyen et al. The first one afforded N

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

• distinguished these alcohols by selective protection of the OH-7 functionality as 2,7-anhydro-Neu5Ac, leaving position OH-4 free for glycosylation upon protection of the vicinal OH-8 and OH-9 substituents as benzylidene or acetonide rings [6]. The formation of the bicyclo[3.2.1] backbone of 2,7-anhydro-Neu5Ac

Construction of trisubstituted chromone skeletons carrying electron-withdrawing groups via PhIO-mediated dehydrogenation and its application to the synthesis of frutinone A

• Qiao Li,
• Chen Zhuang,
• Donghua Wang,
• Wei Zhang,
• Rongxuan Jia,
• Fengxia Sun,
• Yilin Zhang and
• Yunfei Du

Beilstein J. Org. Chem. 2019, 15, 2958–2965, doi:10.3762/bjoc.15.291

• ][76][77], converting alkynes and alkenes to ketones [78], oxidizing alcohols to aldehydes [79][80], as well as in the direct α-hydroxylation of ketones [81]. Furthermore, it could also be used to realize oxidative C–C [82], C–N [83], and C–O [84] bond formations. However, to the best of our knowledge

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

• Chiral hydrogen-bond-donating organocatalysts such as thioureas, squaramides, or alcohols failed to catalyze the Ireland–Claisen rearrangement of silyl ketene acetals. Comparison experiments showed that increasing catalyst loading gradually slowed-down the reaction. DFT calculations using long-range

Diversity-oriented synthesis of spirothiazolidinediones and their biological evaluation

• Sambasivarao Kotha,
• Gaddamedi Sreevani,
• Lilya U. Dzhemileva,
• Milyausha M. Yunusbaeva,
• Usein M. Dzhemilev and
• Vladimir A. D’yakonov

Beilstein J. Org. Chem. 2019, 15, 2774–2781, doi:10.3762/bjoc.15.269

• dipropargyl derivatives 7e and 7f were then treated with different propargyl alcohols 16 in the presence of Wilkinson’s catalyst/Ti(OiPr)4 under ethanol reflux conditions [53] to obtain the corresponding [2 + 2 + 2] cyclotrimerized alcohols 17–19 and 21 in good yields. During the [2 + 2 + 2] cycloaddition of

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

• catalyze the enantioselective hydrogenation of prochiral ketones 18. The prochiral ketones such as acetophenone, 1-tetralone and 1-indanone were reduced to their corresponding alcohols 20a, 20b and 20c, respectively, with moderate optical yields, with formation of (S) as major enantiomer (Scheme 5). After

• mixture during the electroreduction of acetophenone on a mercury cathode induces optical activity in the product (alcohol 24a, Scheme 7) [29]. Additionally, pinacol (23) was also obtained via dimerization along with chiral alcohols. The same method was reinvestigated by Wang and Lu in 2013 using a silver

• reduction of prochiral ketones 34 to their corresponding alcohols 35 at mercury pool in the presence of (−)-N,N'-dimethylquininium tetrafluoroborate (DMQ·2BF4) as chiral inductor using catalytic amounts of (1R,2S)-(−)-N,N'-dimethylephedrinium tetrafluoroborate (Scheme 14) [42][43]. Kawabata and Yoneyama, in

Synthetic terpenoids in the world of fragrances: Iso E Super^® is the showcase

• Alexey Stepanyuk and
• Andreas Kirschning

Beilstein J. Org. Chem. 2019, 15, 2590–2602, doi:10.3762/bjoc.15.252

• . described a process, which involves methanol and other alcohols or alternatively organic acids as nucleophilic additives that can reversibly be introduced and removed again (Scheme 8). Typically, methanol, ethanol, isopropanol and 2-methoxyethanol served as suitable alcohols. According to patent information

• formation of products. Most importantly, Iso E Super® (33), Iso E Super Plus® (34) and Iso Gamma (55) are formed [1]. All compounds are obtained as racemates [25]. Isomerisation using additives such as alcohols or carboxylic acids. The product with the γ-positioned double bond is the desired Iso E Super

Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

• Aydan Yadigarli,
• Qimeng Song,
• Sergey I. Druzhinin and
• Holger Schönherr

Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248

• anomalous fluorescence red shift of fluorophores in alcohols [44]. The additional red shift of NR in protic solvents, such as alcohols and probably chloroform, is associated with the hydrogen-bond formation with the carbonyl group of the dye [45]. The fluorescence maxima of NR in highly polarizable toluene

• intramolecular charge transfer state of 4-(diisopropylamino)benzonitrile (DIABN). Data for all solvents except for the alcohols are fitted well to the linear Equation 8 with a positive slope βf = 0.434. The value of 19.16 ± 0.19 D agrees well with that determined from the solvatochromic expressions (Equations 1

A toolbox of molecular photoswitches to modulate the CXCR3 chemokine receptor with light

• Xavier Gómez-Santacana,
• Sabrina M. de Munnik,
• Tamara A. M. Mocking,
• Niels J. Hauwert,
• Shanliang Sun,
• Prashanna Vijayachandran,
• Iwan J. P. de Esch,
• Henry F. Vischer,
• Maikel Wijtmans and
• Rob Leurs

Beilstein J. Org. Chem. 2019, 15, 2509–2523, doi:10.3762/bjoc.15.244

• was selectively reduced with DIBAL-H to benzyl alcohols 23f–h, which were oxidized with Dess–Martin periodinane to the corresponding benzaldehyde 26f–h. Reductive amination of 26f–h with 7 gave the tertiary amines 13f–h. Methylation with iodomethane and subsequent precipitation gave 3f–h as orange

Chiral terpene auxiliaries V: Synthesis of new chiral γ-hydroxyphosphine oxides derived from α-pinene

• Anna Kmieciak and
• Marek P. Krzemiński

Beilstein J. Org. Chem. 2019, 15, 2493–2499, doi:10.3762/bjoc.15.242

• phosphine oxide P–H nucleophiles were also realized [15]. The phosphine oxide group can also be introduced starting from allylic alcohols employing the rearrangement of allylic diphenylphosphinites to allylphosphine oxides [16][17]. Recently, we have shown the synthesis and applications of chiral PHOX

• synthesis of monoterpene derived ligands, we have utilized commercially available (1R)-α-pinene and (1S)-β-pinene to obtain regioisomeric exocyclic and endocyclic allylic alcohols, which were applied for the synthesis of γ-hydroxydiphenylphosphine ligands. To the best of our knowledge, only Knochel and co

• -workers synthesized diphosphines with a pinane framework [19]. Results and Discussion Synthesis of allylic alcohols In the first step, commercially available natural (1R)-α-pinene (1) was oxidized with lead(IV) acetate to produce (+)-verbenone (2) in 58% yield (Scheme 1) [20]. Hydrogenation of 2 with

Thermal stability of N-heterocycle-stabilized iodanes – a systematic investigation

• Andreas Boelke,
• Yulia A. Vlasenko,
• Mekhman S. Yusubov,
• Boris J. Nachtsheim and
• Pavel S. Postnikov

Beilstein J. Org. Chem. 2019, 15, 2311–2318, doi:10.3762/bjoc.15.223

• extensively, the chemical design of the stabilizing donor ligand L2 has not been investigated as intensive. In general, carboxylic acid derivatives, ethers or free alcohols are utilized to stabilize the hypervalent iodine center by an oxygen–iodine bond or through dative oxygen–iodine interactions in (pseudo

Functionalization of 4-bromobenzo[c][2,7]naphthyridine via regioselective direct ring metalation. A novel approach to analogues of pyridoacridine alkaloids

• Benedikt C. Melzer,
• Alois Plodek and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2304–2310, doi:10.3762/bjoc.15.222

• 5-subsituted products (Scheme 1). Quenching of metalated 9d with aldehydes 11a–d while warming to room temperature led to the formation of the expected racemic secondary alcohols 12a–d in moderate to good yields (50–66%, Scheme 1). Any attempts to improve the yields failed. The use of 2.2

• ]naphthyridine (9d) and subsequent conversion into secondary alcohols by reaction with (hetero)aromatic aldehydes. Outcome of a D2O quenching experiment after metalation of 4-bromobenzo[c][2,7]naphthyridine (9d). Synthesis of 5-substituted 4-bromobenzo[c][2,7]naphthyridines via regioselective metalation of 9d

Synthesis of acremines A, B and F and studies on the bisacremines

• Nils Winter and
• Dirk Trauner

Beilstein J. Org. Chem. 2019, 15, 2271–2276, doi:10.3762/bjoc.15.219

• both secondary allylic alcohols and afforded 2 in good overall yield (Scheme 3). Bisacremine E (7) was proposed to be formed in nature via [4 + 2] cycloaddition involving two acremine F (5) units [4]. Although dimerization of 5 through a Diels–Alder cycloaddition is not electronically favorable, we

• enhance the stability of the molecule, and therefore prevent decomposition, by protection of the non-participating alcohols and attempts to generate the allylic cation from a cyclic ketal [10][11][12], aiming for a Gassman-type reaction mechanism, were also unfruitful. While radical cations are known to

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• , promoting the C–F over C–O bond formation via an inner-sphere pathway. Fluorination of arenes, aryl bromides, -alcohols, -triflates, and -boronic acid derivatives: In 2013, Larhed and co-workers [51] established a one-pot, two-step fluorination of aryl alcohols via aryl nonafluorobutylsulfonates. This

• transformation employed Pd2(dba)3/t-BuBrettPhos and CsF to convert aryl alcohols to aryl fluorides at 180 °C under microwave conditions (Scheme 14). The proposed catalytic cycle of this aryl fluorination is also shown. Only reductive elimination was investigated by Larhed, because this reaction step is crucial

• developed independently by the groups of Buchwald [111] and Wang [112] (Scheme 54). Under similar mild conditions using Togni's reagent II, the desired allyl–CF3 products were obtained and the methods well tolerated a variety of functional groups (e.g., esters, epoxides, amides, alcohols, or aldehydes

Harnessing enzyme plasticity for the synthesis of oxygenated sesquiterpenoids

• Melodi Demiray,
• David J. Miller and
• Rudolf K. Allemann

Beilstein J. Org. Chem. 2019, 15, 2184–2190, doi:10.3762/bjoc.15.215

• ]. Both of these alcohols were methylated with methyl iodide to yield 16 and 17 [32]. To produce the final FDP analogues, THP was removed to generate alcohols 18 and 19, and subsequently diphosphorylated via halogenated intermediates (Scheme 2 and Supporting Information File 1) [33][34][35]. GC–MS

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

• , 4) as an organocatalyst and meso-tetraphenylporphyrin (H2TPP, 5) as a photosensitizer followed by in situ reduction with NaBH4, proceeded similarly to the reported results for simple, achiral aldehydes giving the desired diols 6–8 in 31–41% yields with moderate conversion and alcohols 9–11 as

Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via intramolecular 1,3-dipolar cycloaddition

• Yulia V. Khoroshunova,
• Denis A. Morozov,
• Andrey I. Taratayko,
• Polina D. Gladkikh,
• Yuri I. Glazachev and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2019, 15, 2036–2042, doi:10.3762/bjoc.15.200

• C11H18NO2, which matches element analysis data. These results allowed us to assign the structure 15 to this nitroxide. Indeed, oxidation of amines with peracids is known to proceed via oxoammonium cation formation [17][18], and the latter can oxidize alcohols to carbonyl compounds [19]. The close proximity