Is the tungsten(IV) complex (NEt₄)₂[WO(mnt)₂] a functional analogue of acetylene hydratase?

• Matthias Schreyer and
• Lukas Hintermann

Beilstein J. Org. Chem. 2017, 13, 2332–2339, doi:10.3762/bjoc.13.230

• recent works favor nucleophilic addition of water to tungsten-coordinated 2 with assistance of a catalytic carboxylate as key-step (Scheme 1b), followed by protonation of the intermediary 2-hydroxyethenyltungstate to release vinyl alcohol [10][11][12]. In 1997, Sarkar et al. reported that the oxidation

• the strongly alkaline reaction medium [18]. Base-mediated hydration is possible for π-acceptor substituted alkynes, but nucleophilic addition of secondary amines followed by acidic hydrolysis to the carbonyl compound is usually preferred [18]. The discovery of a tungsten-based enzyme with ethyne

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• nucleophilic addition of C-substituted malonic esters 17 to 4-tert-butylnitrosocyclohexene NSA3 (generated either from TBS ether 18 or free oxime 19) proceeds with high stereoselectivity and affords mainly or exclusively the trans-isomers of adducts 20 (Scheme 8) [29]. Expectedly, the stereoselectivity of the

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• is illustrated by the recent works reporting the reaction of bis(diethylamino)chlorophosphine (95) with the acetal 96 in the presence of a Lewis acid to yield the phosphonodiamide 97. Then the nucleophilic addition of adenine and the hydrolysis of the phosphonodiamide function in phosphonic acid

• produce compound 98 [213] (Figure 28A). A second example corresponds to the nucleophilic addition of N-heterocyclic phosphine 99 to a nitroalkene (phospho-Michael reaction) as shown in Figure 28B. The thiourea unit in 99 plays a crucial role by assuming intramolecular interaction with the nitro function

• functionalized with three phosphonic acid groups (Figure 29) [24]. The sequence requires the preparation of the 4-fluorophenylphosphonodiamide 107 which is prepared by nucleophilic addition of an aryllithium intermediate (from 105) on chlorophosphadiamide 106. In the last step, the tris(phenylphosphonodiamide

NHC-catalyzed cleavage of vicinal diketones and triketones followed by insertion of enones and ynones

• Ken Takaki,
• Makoto Hino,
• Akira Ohno,
• Kimihiro Komeyama,
• Hiroto Yoshida and
• Hiroshi Fukuoka

Beilstein J. Org. Chem. 2017, 13, 1816–1822, doi:10.3762/bjoc.13.176

• the 9- and 14-membered 1,4-diketones 7b and 7c at elevated temperature, respectively. Next, we investigated the NHC-catalyzed reaction of 1,2,3-triketone 9 with enone 6a. Since the central carbonyl group of 9 could be more electrophilic than the others at 1- and 3-positions, nucleophilic addition of

Effect of uridine protecting groups on the diastereoselectivity of uridine-derived aldehyde 5’-alkynylation

• Raja Ben Othman,
• Mickaël J. Fer,
• Laurent Le Corre,
• Sandrine Calvet-Vitale and
• Christine Gravier-Pelletier

Beilstein J. Org. Chem. 2017, 13, 1533–1541, doi:10.3762/bjoc.13.153

• organometallic reagents onto nucleoside aldehyde (Table 1), we decided to investigate the influence of the protecting groups of the uridine aldehyde on the stereochemical outcome of the nucleophilic addition of a Grignard reagent and we wish to report herein the results of our study. Results and Discussion We

• 5a [51], R1 = TIPS). Some compounds were also N3-allylated (1b, 4b and 5b) to evaluate the possible influence of R2 on the diastereoselectivity of the nucleophilic addition (Scheme 1). Primary alcohols 1–5 were submitted to an oxidation/Grignard addition sequence leading to the corresponding

Syntheses of 3,4- and 1,4-dihydroquinazolines from 2-aminobenzylamine

• Jimena E. Díaz,
• Silvia Ranieri,
• Nadia Gruber and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2017, 13, 1470–1477, doi:10.3762/bjoc.13.145

• functionalized 2-aminobenzylamines [36][37] such as the cyclization of N-(2-aminobenzyl)amides, which in general requires drastic conditions or long reaction times [17][18][21][22][29][38][39][40]. Miscellaneous methods include the nucleophilic addition of secondary amines to carbodiimides followed by an

A new member of the fusaricidin family – structure elucidation and synthesis of fusaricidin E

• Marcel Reimann,
• Louis P. Sandjo,
• Luis Antelo,
• Eckhard Thines,
• Isabella Siepe and
• Till Opatz

Beilstein J. Org. Chem. 2017, 13, 1430–1438, doi:10.3762/bjoc.13.140

• should be generated by nucleophilic addition of an allyl anion equivalent to the resulting aldehyde 5. Guanidine formation and ozonolysis with subsequent oxidation to the carboxylic acid would then furnish the protected GHPD side chain building block 3 which can then be coupled to the cyclodepsipeptide

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

• M. Fernanda N. N. Carvalho,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

• the sultam before the second equivalent undergoes the desired nucleophilic addition to the carbonyl group. All attempts to re-oxidise the sultam 15 to the sulfonimide 13, using Cl2/pyridine [37] or N-tert-butylphenylsulfinimidoyl chloride/DBU [38] under literature conditions, were unsuccessful due to

DMAP-assisted sulfonylation as an efficient step for the methylation of primary amine motifs on solid support

• Johnny N. Naoum,
• Koushik Chandra,
• Dorit Shemesh,
• R. Benny Gerber,
• Chaim Gilon and
• Mattan Hurevich

Beilstein J. Org. Chem. 2017, 13, 806–816, doi:10.3762/bjoc.13.81

• proved highly efficient in solid-phase synthesis of a somatostatin analogue bearing three Nα-methylation sites that could not be synthesized using the previously described state-of-the-art methods. Keywords: N-methylation; nucleophilic addition; solid phase; somatostatin; sulfonylation; Introduction

• calculations provide an explanation to the observed superiority of DMAP over collidine as the lower energy barrier of the DMAP intermediate compared to that of the collidine intermediate is essential for a sulfonylation that proceeds through a nucleophilic addition type mechanism (Figure 1C and 1D). In

• the amine in which the additive acts as a base. The second being a nucleophilic addition type mechanism, in which a stable intermediate is formed between the sulfonyl and the additive. We hypothesized that if the sulfonylation goes through a nucleophilic addition-type mechanism, replacing collidine

Effect of the ortho-hydroxy group of salicylaldehyde in the A³ coupling reaction: A metal-catalyst-free synthesis of propargylamine

• Sujit Ghosh,
• Kinkar Biswas,
• Suchandra Bhattacharya,
• Pranab Ghosh and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 552–557, doi:10.3762/bjoc.13.53

• activate the terminal acetylene primarily, which then undergoes a nucleophilic addition to the iminium electrophile generated from the aldehyde and the amine. Among different transition metals, copper metal has been mostly explored as the catalyst to activate the terminal acetylene, though there is a

• , which then undergoes nucleophilic addition at the electrophilic iminium ion 4, eventually providing the A3 coupled product (Scheme 3). In the absence of the metal catalyst, the sp carbon (C–H) of the alkyne is less nucleophilic in nature. However, after the formation of the iminium ion 4 (as it happens

(Z)-Selective Takai olefination of salicylaldehydes

• Stephen M. Geddis,
• Caroline E. Hagerman,
• Warren R. J. D. Galloway,
• Hannah F. Sore,
• Jonathan M. Goodman and
• David R. Spring

Beilstein J. Org. Chem. 2017, 13, 323–328, doi:10.3762/bjoc.13.35

• )-product (Scheme 6). Our proposed mechanism commences with nucleophilic addition of gem-dichromium species to the aldehyde moiety via a six membered pseudo-chair transition state, as is generally accepted [5][7]. However, rather than proceeding via the transition state which places most groups in a pseudo

Regiochemistry of cyclocondensation reactions in the synthesis of polyazaheterocycles

• Patrick T. Campos,
• Leticia V. Rodrigues,
• Andrei L. Belladona,
• Caroline R. Bender,
• Juliana S. Bitencurt,
• Fernanda A. Rosa,
• Davi F. Back,
• Helio G. Bonacorso,
• Nilo Zanatta,
• Clarissa P. Frizzo and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 257–266, doi:10.3762/bjoc.13.29

• times ranging from 0.5 to 20 h, was not effective in forming the imidazolone of interest. The only product observed was the acylated amidine generated through a nucleophilic addition of the amidine to the ester carbonyl. For the latter compound the best result was obtained for the reaction in ethanol

First DMAP-mediated direct conversion of Morita–Baylis–Hillman alcohols into γ-ketoallylphosphonates: Synthesis of γ-aminoallylphosphonates

• Marwa Ayadi,
• Haitham Elleuch,
• Emmanuel Vrancken and
• Farhat Rezgui

Beilstein J. Org. Chem. 2016, 12, 2906–2915, doi:10.3762/bjoc.12.290

• nucleophilic addition of triethyl phosphite onto Morita–Baylis–Hillman acetates [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. We envisaged in the second part of this study a further functionalization of these allylphosphonates as

cis-Diastereoselective synthesis of chroman-fused tetralins as B-ring-modified analogues of brazilin

• Dimpee Gogoi,
• Runjun Devi,
• Pallab Pahari,
• Bipul Sarma and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2016, 12, 2816–2822, doi:10.3762/bjoc.12.280

• h (entry 1, Table 1) led to the formation of a mixture of two major isolable compounds, out of which one was the expected product (±)-5 (50%) and the remaining one was hexafluoroisopropyl ether (generated from the nucleophilic addition of HFIP on the benzylic position). Meanwhile, we found that

Copper-catalyzed asymmetric sp³ C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

• Pierre Querard,
• Inna Perepichka,
• Eli Zysman-Colman and
• Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

• stereofacial nucleophilic addition of the arylboronic acid to produce the desired enantioenriched arylated product VII. The Ir(III) is regenerated in the presence of the sacrificial external oxidant TBHP. Conclusion In conclusion, we have successfully developed a highly efficient light-mediated coupling method

Selective synthesis of thioethers in the presence of a transition-metal-free solid Lewis acid

• Federica Santoro,
• Matteo Mariani,
• Federica Zaccheria,
• Rinaldo Psaro and
• Nicoletta Ravasio

Beilstein J. Org. Chem. 2016, 12, 2627–2635, doi:10.3762/bjoc.12.259

• nucleophilic substitution mechanism: the higher the electronic density on the carbinol C atom, the higher the reaction rate. When the electronic density is somewhat lower, competitive formation of the ether occurs but subsequent nucleophilic addition of the thiol to the ether restores a very high selectivity

Thiazol-4-one derivatives from the reaction of monosubstituted thioureas with maleimides: structures and factors determining the selectivity and tautomeric equilibrium in solution

• Alena S. Pankova,
• Pavel R. Golubev,
• Alexander F. Khlebnikov,
• Alexander Yu. Ivanov and
• Mikhail A. Kuznetsov

Beilstein J. Org. Chem. 2016, 12, 2563–2569, doi:10.3762/bjoc.12.251

• (Scheme 1). It was reported that the substituent on the maleimide nitrogen atom, particularly a group in the para-position of the phenyl ring in N-arylmaleimides, affects the reactivity of the maleimide toward nucleophilic addition [10]. Strange as it may seem, N-phenylthiourea reacts with N

Highly chemo-, enantio-, and diastereoselective [4 + 2] cycloaddition of 5H-thiazol-4-ones with N-itaconimides

• Shuai Qiu,
• Choon-Hong Tan and
• Zhiyong Jiang

Beilstein J. Org. Chem. 2016, 12, 2293–2297, doi:10.3762/bjoc.12.222

• [6], allylation [7], conjugate addition to enones [8], and γ-addition with allenoates [9]. All these examples focused on nucleophilic addition reactions of the C5 atom of 5H-thiazol-4-ones. Recently, we described an organocatalytic asymmetric [4 + 2] cyclization of 5H-thiazol-4-ones with a series of

p-Nitrophenyl carbonate promoted ring-opening reactions of DBU and DBN affording lactam carbamates

• Madhuri Vangala and
• Ganesh P Shinde

Beilstein J. Org. Chem. 2016, 12, 2086–2092, doi:10.3762/bjoc.12.197

• if the reaction favors both – nucleophilic addition as well as substitution – at lower temperature, the reaction was performed at room temperature for 1.5 h. Although both products were observed the substitution product was minor product, as seen by the integration of p-nitrophenol peaks in the 1H

• nucleophilicity of DBU/DBN and highly electrophile p-nitrophenyl carbonate derivatives. The reactions proceeded even at room temperature and displayed the nucleophilic addition and substitution with the p-nitrophenyl carbonate derivative of 10-bromodecanol. These caprolactam derivatives may find application in

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

• hindrance of the AMIM cation with respect to the BMIM cation, the latter exerting less effective interactions with the corresponding (imidazolium) anion. Regardless of its nature, the cation might also activate DMC towards nucleophilic addition: a cooperative nucleophilic–electrophilic mechanism could

Synthesis of pyrrolo[2,1-f][1,2,4]triazin-4(3H)-ones: Rearrangement of pyrrolo[1,2-d][1,3,4]oxadiazines and regioselective intramolecular cyclization of 1,2-biscarbamoyl-substituted 1H-pyrroles

• Kkonnip Son and
• Seong Jun Park

Beilstein J. Org. Chem. 2016, 12, 1780–1787, doi:10.3762/bjoc.12.168

• 1, Table 2). In the cases of Li[Me3AlSPh], NaSMe, and NaOMe, the triazinone 12a was readily obtained after the nucleophilic-addition/ring-closure reaction (entries 2–5, Table 2). For example, similar to benzoxazine [22], treatment of 11a and 11d with lithium trimethyl(phenylsulfido)aluminate Li

TMSBr-mediated solvent- and work-up-free synthesis of α-2-deoxyglycosides from glycals

• Mei-Yuan Hsu,
• Yi-Pei Liu,
• Sarah Lam,
• Su-Ching Lin and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2016, 12, 1758–1764, doi:10.3762/bjoc.12.164

• sequential steps (Scheme 1). Monosaccharide acceptor 64 underwent the TMSBr-mediated nucleophilic addition to glucal 1 to produce exclusively disaccharide 65 (97%, α:β = 7:1) in an excellent yield with high α-selectivity. Remarkably, the 1-thiol group remained intact after the formation of disaccharide 65

• that the acid-catalysed nucleophilic addition of an alcohol to a glycal is likely to proceed through the formation of an oxocarbenium ion via the protonation at C2 [6][63]. In the presence of TPPO, the oxocarbenium cation is stabilized by the ion–dipole interaction with TPPO oriented preferably at the

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• [222]. The tetramolecular transition states TS1 and TS2 are considered to be the two key steps determining the course of the oxidation: the nucleophilic addition of a peroxy acid molecule to ketone (TS1) and the migration of R and cleavage of O–O bond (TS2). Thus, electrophilic substrates favor TS1 and

Enantioselective addition of diphenyl phosphonate to ketimines derived from isatins catalyzed by binaphthyl-modified organocatalysts

• Hee Seung Jang,
• Yubin Kim and
• Dae Young Kim

Beilstein J. Org. Chem. 2016, 12, 1551–1556, doi:10.3762/bjoc.12.149

• few decades [20][21][22]. General approaches for the synthesis of chiral 3-substituted-3-aminooxindole derivatives include the amination of various 3-monosubstituted oxindoles [23][24][25][26][27] and the nucleophilic addition to ketimines derived from isatin derivatives [28][29][30][31][32][33][34

• ). The nucleophilic addition of diphenyl phosphonate (2) to ketimine 2l derived from N-unprotected isatin was also studied. The adduct 3l was isolated in 74% yield with 73% ee (Table 2, entry 12). Unfortunately, the reaction of diphenyl phosphonate (2) with N-Boc-ketimine 2m provided adduct 3m with low

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• are biosynthesised in seven principal ways (Scheme 2). Those comprise nucleophilic addition of a hydroxy group to electrophiles like epoxides 4, carbonyl groups 6 or Michael acceptors 9, potentially followed by further processing (a–c in Scheme 2). Lactones 12 are formed by transacylation of a