Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

• Thaipparambil Aneeja,
• Cheriya Mukkolakkal Abdulla Afsina,
• Padinjare Veetil Saranya and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

• single-step. The proposed mechanism is depicted in Scheme 26. Xiao and co-workers developed an environmentally benign strategy for the oxidative cyanation of differently substituted alcohols using a manganese oxide nanorod-supported ruthenium catalyst (Scheme 27) [49]. They also evaluated the efficiency

• of other metals such as Au, Pt, Pd, Rh, Ag, and Fe and found that they were less efficient compared to Ru. The benzylic alcohols showed higher reactivity than aliphatic alcohols towards this methodology. Moreover, this protocol worked well for differently substituted heterocyclic alcohols and

• catalyst. Synthesis of cyanated isoxazolines from alkenyl oximes catalyzed by [RuCl2(p-cymene)]2 in the presence of tert-butyl nitrite. Proposed mechanism for the synthesis of cyanated isoxazolines from alkenyl oximes. Oxidative cyanation of differently substituted alcohols. Cyanation of tertiary amines

A photochemical C=C cleavage process: toward access to backbone N-formyl peptides

• Haopei Wang and
• Zachary T. Ball

Beilstein J. Org. Chem. 2021, 17, 2932–2938, doi:10.3762/bjoc.17.202

• -nitroaryl compounds. Various 2-nitrobenzyl derivatives are used to photocage heteroatom functional groups, including alcohols, amines, carboxylic acids, and phosphates [11]. Typical photochemical pathways result in cleavage of a benzylic C–X bond following initial benzylic H-atom abstraction [11][13]. In

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

• -disubstituted counterparts, perhaps due to the generation of the more stable 3° radical intermediate. In the following year, Song and Li reported a reaction shortcut for the carbonyl-arylation of N-arylacrylamides 60 through the in-situ oxidation of alcohols 67 (Scheme 11) [84]. Under the optimized reaction

• conditions, both primary and secondary alcohols are oxidized to the corresponding aldehyde/ketone, so the chronology of the addition remains unclear whether the reaction proceeds exclusively via an alkyl radical followed by subsequent oxidation, an acyl radical, or a combination of both. Further, slight

• alcohols 67 and aliphatic acids 173 (Scheme 37) [144]. Through a DCC-mediated dehydrogenative condensation with hydroperoxides, carboxylic acids could generate alkyl diacyl peroxides and peresters in situ. Decarboxylation followed by radical addition across the alkene 108 would generate a succeeding alkyl

Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

• Lukáš Ďurina,
• Anna Ďurinová,
• František Trejtnar,
• Ľuboš Janotka,
• Lucia Messingerová,
• Jana Doháňošová,
• Ján Moncol and
• Róbert Fischer

Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188

• formation. Since the aqueous tungstic acid-catalyzed hydrogen peroxide epoxidations of monosubstituted allylic alcohols usually proceed in anti (erythro) stereoselective fashion [32], we propose that the high syn selectivity can be attributed to the presence of the unprotected hydroxy group in the

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• atroposelective synthesis of axially chiral biarylamino alcohols from the reaction of quinone ester (3) and various 2-naphthylamines 4. In the presence of CPA 2, the axially chiral biarylamino alcohols 5 were obtained in moderate to good yields (up to 85%) and high to excellent enantioselectivities (up to 99% ee

• enantioselectivity (91:9 to 98:2 er, Scheme 15) [65]. In addition, the authors also succeeded in preparing naphthylindoles 46, which exhibit both axial and central chirality, through the addition reaction of racemic naphthylindoles 42 and o-hydroxybenzyl alcohols 45 using chiral phosphoric acid CPA 13. This reaction

• -trifluoromethylpropargyl alcohol are very important for the reaction. Li and co-workers developed a chiral phosphoric acid-catalyzed asymmetric remote 1,8-conjugate addition of thiazolones 111 and azlactones 112 to propargyl alcohols 110 for the synthesis of the chiral allenes 113 and 114, respectively. In the presence of

Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181

• cyclization of primary alcohols like 2k has been successfully utilized in the synthesis of fluorenones and azafluorenones [37], however, the authors used TBHP in n-decane. We repeated the reaction for primary amine 2a, primary alcohol 2k, as well as aldehyde 2l with TBHP in n-decane and obtained fluorenone (3

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• aliphatic alcohols. In 2015, Ackermann’s group [88] disclosed the visible light-induced copper-catalyzed arylation of azoles. In this case, the mechanistic studies revealed that amino acid ligands accelerated the cross-coupling (Scheme 22). In 2020, a visible-light-induced copper-catalyzed arylation of C

• photoinduced copper-catalyzed α-C(sp3)–H cyclization of aliphatic alcohols with o-aminobenzamide. However, the aliphatic alcohols were limited to methanol and ethanol. In this transformation, α-C(sp3)–H of MeOH/EtOH undergoes a hydrogen atom transfer (HAT) process to synthesize quinazolinones involving ligand

Direct C(sp³)–H allylation of 2-alkylpyridines with Morita–Baylis–Hillman carbonates via a tandem nucleophilic substitution/aza-Cope rearrangement

• Siyu Wang,
• Lianyou Zheng,
• Shutao Wang,
• Shulin Ning,
• Zhuoqi Zhang and
• Jinbao Xiang

Beilstein J. Org. Chem. 2021, 17, 2505–2510, doi:10.3762/bjoc.17.167

• . However, these reactions were mainly suitable to strong nucleophiles such as malonates, amines, or alcohols etc. [20][21][22][23]. The allylic substitution reactions using some weak nucleophiles, such as alkyl aza-arenes, were very limited [24][25][26][27][28][29]. In 2014, Rios and coworkers developed a

Targeting active site residues and structural anchoring positions in terpene synthases

• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 2441–2449, doi:10.3762/bjoc.17.161

• incorporated by its nucleophilic attack at a cationic intermediate, leading to terpene alcohols [5][6] or sometimes ethers [7][8]. Substrate ionisation by TPSs is achieved through binding of the diphosphate portion to a trinuclear Mg2+ cluster in the active site that is itself bound to two highly conserved

Allylic alcohols and amines by carbenoid eliminative cross-coupling using epoxides or aziridines

• Matthew J. Fleming and
• David M. Hodgson

Beilstein J. Org. Chem. 2021, 17, 2385–2389, doi:10.3762/bjoc.17.155

• α-lithio ethers, to give convergent access to allylic alcohols and allylic amines, respectively. The process can be considered as proceeding by selective strain-relieving attack (ring-opening) of the lithiated three-membered heterocycle by the lithio ether and then selective β-elimination of lithium

• stereoselectivity. However, neither isopropyl or neopentyl benzylic ethers 26 and 27 [23][24] led to a significant change in the E/Z ratio for cinnamylamine 23 (Scheme 11). Conclusion In summary, we report a new, convergent access to allylic alcohols and amines. The process proceeds by selective cross-coupling of α

• -lithio epoxides or aziridines [3][4][5]. Proposed eliminative cross-coupling of carbenoids to allylic alcohols (X = O) or allylic amines (X = NSO2t-Bu). Allylic alcohol 6 by one-carbon homologation from epoxide 5. Internal allylic alcohols from epoxides and stannane 7. Cyclopropylidene synthesis from

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

• effect of H2O (protic solvent) in the reaction media [48]. Pulido et al. had developed a conversion of allylsilyl alcohols 19 to diastereomeric mixtures of tetrahydrofuran derivatives 20A and 20B (Scheme 9) [47]. It was reported that more substituted alkyl groups present in allylsilyl alcohol 20b direct

• had also performed experiments with different isoprenoid derivatives (carboxylic acid, ketones alcohols, and keto esters) to form different bicyclic products (Scheme 19). A Hg(II)-salt-promoted cyclization of amidal 56 was performed to synthesize optically active cyclic alanine derivatives 57 as 1:1

• electrophilic addition (Scheme 26). Schwartz et al. developed a new route for the synthesis of exocyclic enol ether 83 and endocyclic enol ether 85 involving a Hg(II)-induced cyclization of acetylenic alcohols 82 and 84, respectively [79]. This work revealed that the regioselectivity of the Hg(II) addition to

Halides as versatile anions in asymmetric anion-binding organocatalysis

• Lukas Schifferer,
• Martin Stinglhamer,
• Kirandeep Kaur and
• Olga García Macheño

Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145

• . Enantioselective tail-to-head cyclization of neryl chloride derivatives. Cation–π interactions in anion binding-catalyzed asymmetric addition reactions: a) addition of indoles to pyrones and b) allylation of α-chloro glycinates. Bisthiourea catalyzed oxa-Pictet–Spengler reaction of indole-based alcohols and

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• the oxidative addition of the nickel(0) catalyst 6-VI to aryl bromide 3b. The photochemical nickel catalysis is not limited to an α-oxy C(sp3)‒H arylation of ethers. MacMillan and co-workers disclosed a method for the selective direct α-arylation of alcohols 18 using photoredox, HAT, and nickel triple

Transition-metal-free intramolecular Friedel–Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives

• Tülay Yıldız,
• İrem Baştaş and
• Hatice Başpınar Küçük

Beilstein J. Org. Chem. 2021, 17, 2203–2208, doi:10.3762/bjoc.17.142

• alcohols with diaryliodonium salts [26], the Sc(OTf)3-catalyzed domino reaction [27], and the iodine-catalyzed nucleophilic substitution reaction of xanthen-9-ol [28]. As an example of an intramolecular hydroarylation of an olefin, 9,10-dihydroacridines, which are N derivatives of xanthenes, were

• arenes using the FCA methods with π-activated alcohols and organocatalysts has begun to be preferred over using conventional reagents, such as organohalogens and transition metal catalysts, which are toxic and require working under harsher conditions [38]. After these developments, the intramolecular FCA

• method using π-activated alcohols has frequently been used for xanthene synthesis. Some of these methods are the stereoselective synthesis of 9-vinyl-substituted unsymmetrical xanthenes and thioxanthenes by intramolecular FCA reaction [39], Lewis acid-catalyzed intramolecular FCA [40], and the synthesis

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

• opening of these latter with alcohols 8 was efficient again and allowed the preparation of new reagents in good yields, after a second aqueous work-up. Using this approach, SMAHOs bearing a benzyl (4da) or a (−)-menthyl group (4ea) were easily prepared with good overall yields (49–71%). Despite its

• . SMAHOs bearing classical ester groups could be obtained in moderate yields (iPr: 51%; Bn: 53%; allyl: 52%) and the use of less nucleophilic alcohols such as t-BuOH, 2,2,2-trifluoroethanol, (−)-menthol, and phenol led to decreased yields (37%, 34%, 28%, and 17%, respectively). More functionalized alcohols

A study on selective transformation of norbornadiene into fluorinated cyclopentane-fused isoxazolines

• Zsanett Benke,
• Attila M. Remete and
• Loránd Kiss

Beilstein J. Org. Chem. 2021, 17, 2051–2066, doi:10.3762/bjoc.17.132

• the selectivity of olefin bonds during a CM reaction [38][39][40][41][42][43]. Investigations of various types of olefins in CM, such as substituted and functionalized styrenes, unsaturated tertiary alcohols, olefins with quaternary carbon centers, acrylates, allyl ethers or allyl acetates gave a

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• [11][12], the 2,2’-bianthracene derivative 3 provides a green and fluorescent OLED [13], 2,2’-bianthracenyl (4) has been employed as an organic semiconductor in an OFET device [14], and di-n-alkoxyanthracenes have gelling properties with diverse solvents, mainly alkanes and alcohols [4]. Furthermore

• -cyclotrimerization reaction catalyzed by a cobalt/zinc reagent [40]. With regard to substituted anthracenes, this method consisted of a [2 + 2 + 2] cycloaddition reaction of 1,6-diynes 27 with 4-aryl-2-butyn-1-ols 28 (Scheme 6). The authors converted the resulting benzylic alcohols 29 to the corresponding aldehydes

• the representative examples 194a–d [81]. In 2017, Mal and Basak applied a [4 + 2] anionic annulation of substituted cyanophthalides 195 with dienoates 196 and obtained 3-allylnaphthoates 197 (Scheme 46) [82]. Then, they converted the naphthoate derivatives 197 to the corresponding alcohols 198 by

Asymmetric organocatalyzed synthesis of coumarin derivatives

• Natália M. Moreira,
• Lorena S. R. Martelli and
• Arlene G. Corrêa

Beilstein J. Org. Chem. 2021, 17, 1952–1980, doi:10.3762/bjoc.17.128

• gram-scale experiment, affording the desired product 21a with excellent yield and ee (Scheme 6b). Ren et al. reported an enantioselective reaction of cyclopent-2-enone-derived Morita–Baylis–Hillman (MBH) alcohols 24 with 4-hydroxycoumarins 1 catalyzed by a chiral primary amine derived from

• reaction of cyclopent-2-enone-derived MBH alcohols 24 with 4-hydroxycoumarins 1. Sequential Michael addition/hydroalkoxylation one-pot approach to annulated coumarins 28 and 30. Michael addition of 4-hydroxycoumarins 1 to enones 2 using a binaphthyl diamine catalyst 31. Asymmetric Michael addition of 4

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• numbers. The V(II) and V(V) species are reducing and oxidizing agents, respectively, whereas V(IV) is often encountered, mainly in the form of dioxovanadium ion VO2+ center [76]. Vanadium-based compounds have been reported to mediate the oxidation of alkanes to alcohols and ketones [76]. The reactions are

• heterogeneous vanadium-based catalysts have been employed to obtain alcohols and carbonyl compounds through oxidation, including VOSO4, Na(VO3), VO(acac)2, VOX3, among others. Obtaining ketones and aldehydes from hydrocarbon compounds through vanadium-mediated activation of C(sp3)–H bonds in a benzylic position

• reaction suggested it goes through a radical pathway. Similar to the oxidation of alkanes to give alcohols and carbonyl compounds, vanadium complexes have been reported to mediate the hydroxylation of arenes, including the obtaining of phenol from benzene. However, most mechanistic studies provided

Cerium-photocatalyzed aerobic oxidation of benzylic alcohols to aldehydes and ketones

• Girish Suresh Yedase,
• Sumit Kumar,
• Jessica Stahl,
• Burkhard König and
• Veera Reddy Yatham

Beilstein J. Org. Chem. 2021, 17, 1727–1732, doi:10.3762/bjoc.17.121

• , Universitätstraße 31, D-93053 Regensburg, Germany 10.3762/bjoc.17.121 Abstract We have developed a cerium-photocatalyzed aerobic oxidation of primary and secondary benzylic alcohols to aldehydes and ketones using inexpensive CeCl3·7H2O as photocatalyst and air oxygen as the terminal oxidant. Keywords: alcohol

• ; aldehydes; cerium; oxidation; ketones; visible light; Introduction The selective oxidation of alcohols to carbonyl compounds [1][2] is an important process for producing a wide range of value-added fine chemicals [3][4][5][6]. In the traditional oxidation process stoichiometric amounts of oxidants such as

• thermal conditions. Significant advances were made for the oxidation of benzylic alcohols by using metal-based photocatalysts [38][39][40][41][42][43][44][45][46] and metal-free photocatalysis [47][48][49][50][51][52][53] in combination with various oxidants, such as TBHP and DDQ [54][55]. However, the

Volatile emission and biosynthesis in endophytic fungi colonizing black poplar leaves

• Christin Walther,
• Pamela Baumann,
• Katrin Luck,
• Beate Rothe,
• Peter H. W. Biedermann,
• Jonathan Gershenzon,
• Tobias G. Köllner and
• Sybille B. Unsicker

Beilstein J. Org. Chem. 2021, 17, 1698–1711, doi:10.3762/bjoc.17.118

• blends of these endophytes grown on agar medium consist of typical fungal compounds, including aliphatic alcohols, ketones and esters, the aromatic alcohol 2-phenylethanol and various sesquiterpenes. Some of the compounds were previously reported as constituents of the poplar volatile blend. For one

• ]. Endophytic fungi themselves can produce VOCs. Currently, around 300 fungal VOCs have been characterized, including aliphatic alcohols, ketones, aldehydes, acids and esters, terpenoids, benzenoids, naphthalene derivatives, and cycloalkanes [25][26][27]. Endophytic fungal VOCs are frequently described to

• ), sesquiterpenes like α-farnesene, chamigrene (4), aromatic alcohols like 2-phenylethanol (3), and aliphatic alcohols like 3-methyl-1-butanol (6) are also found in the headspace of endophytic fungi grown in culture [46][47][48][49][50][51][52]. Those studies have shown that volatile blends produced by some

Electron-rich triarylphosphines as nucleophilic catalysts for oxa-Michael reactions

• Susanne M. Fischer,
• Simon Renner,
• A. Daniel Boese and
• Christian Slugovc

Beilstein J. Org. Chem. 2021, 17, 1689–1697, doi:10.3762/bjoc.17.117

• triphenylphosphine (TPP) in catalyzing oxa-Michael additions. A matrix consisting of three differently strong Michael acceptors and four alcohols of varying acidity was used to assess the activity of the three catalysts. All test reactions were performed with 1 mol % catalyst loading, under solvent-free conditions

• and at room temperature. The results reveal a decisive superiority of TMTPP for converting poor and intermediate Michael acceptors such as acrylamide and acrylonitrile and for converting less acidic alcohols like isopropanol. With stronger Michael acceptors and more acidic alcohols, the impact of the

• -Michael addition. Triphenylphosphine (TPP), (4-methoxyphenyl)diphenylphosphine (MMTPP) and tris(4-trimethoxyphenyl)phosphine (TMTPP). The catalysts were investigated in the reaction of four different Michael acceptors with four different alcohols. In the oxa-Michael addition, the zwitterion i, initially

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• hydroalkylation cascades. In 2016, the Cui group reported the hydroalkylation of olefins 59 using p-quinone methides 60 as electrophilic partners (Scheme 24A) [91]. Alkenyl alcohols could be employed without needing to protect the hydroxy functional group, and the acidity of the phenolic hydrogen present in the

• additions [92]. Using MBH acetates 63 as substrates, olefin hydroallylation products 64 were obtained via E1cB elimination of the acetate leaving group driven by the enolate intermediate (Scheme 25B). Six-membered lactones (Scheme 25A, 65a–c) were obtained in a cascade reaction when alkenyl alcohols were

• as Mn(0) and MnO2, that had been employed in the previous work by the same authors to ensure catalytic turnover [110]. Substrates containing functional groups, like esters, phthalimides, silyl enol ethers, boronates, ketones, tertiary alcohols, epoxides, and cyclobutanes, were compatible with the

Cascade intramolecular Prins/Friedel–Crafts cyclization for the synthesis of 4-aryltetralin-2-ols and 5-aryltetrahydro-5H-benzo[7]annulen-7-ols

• Jie Zheng,
• Shuyu Meng and
• Quanrui Wang

Beilstein J. Org. Chem. 2021, 17, 1481–1489, doi:10.3762/bjoc.17.104

• [10][11][12][13][14]. For example, Nagumo and coworkers have developed a Prins/Friedel–Crafts cyclization of homocinnamyl alcohols with aromatic aldehydes under the action of BF3·Et2O affording 2H-indeno[1,2-b]furan derivatives [15]. Likewise, Hinkle and coworkers reported in 2017 a three-step domino

Icilio Guareschi and his amazing “1897 reaction”

• Gian Cesare Tron,
• Alberto Minassi,
• Giovanni Sorba,
• Mara Fausone and
• Giovanni Appendino

Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93

• File 1, third paragraph). Despite the poverty of means, Guareschi established a laboratory in Livorno, carrying out independent research in the realm of organic chemistry. In 1874, Guareschi reported the reduction of amides to aldehydes and alcohols with sodium amalgam [23], nowadays an obsolete

• alcohol side product was not labeled, suggesting that alcohols are formed by radical trapping by oxygen and the intermediate formation of hydroperoxides. Conversely, cations would have been trapped by water, resulting in the formation of labeled alcohols. Cyclic voltammetry experiments showed an