Vicinal difunctionalization of alkenes by four-component radical cascade reaction of xanthogenates, alkenes, CO, and sulfonyl oxime ethers

• Shuhei Sumino,
• Takahide Fukuyama,
• Mika Sasano,
• Ilhyong Ryu,
• Antoine Jacquet,
• Frédéric Robert and
• Yannick Landais

Beilstein J. Org. Chem. 2019, 15, 1822–1828, doi:10.3762/bjoc.15.176

• reaction using xanthogenates, alkenes, and sulfonyl oxime ethers (Scheme 1, reaction 1) [21][22]. The reaction proceeds efficiently to provide good yields of α-alkoxyimino esters, potential precursors of lactams, lactones and β-keto esters. Since the three-component radical reaction involving alkyl halides

Metal-free mechanochemical oxidations in Ertalyte^® jars

• Andrea Porcheddu,
• Francesco Delogu,
• Lidia De Luca,
• Claudia Fattuoni and
• Evelina Colacino

Beilstein J. Org. Chem. 2019, 15, 1786–1794, doi:10.3762/bjoc.15.172

• reactions of hydantoins [41][59]. However, also using this oxidant, we observed low conversions (31%) and the formation of significant amounts of byproducts, mainly halides and olefins (elimination byproducts). The use of liquid-assisted grinding (LAG) procedures [60][61][62] by adding small quantities of

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• oxidation states (Cu(0), Cu(I), Cu(II), and Cu(III)). Copper has been known for a long time to act as a catalyst for cross-coupling reactions (Ullmann–Goldberg reaction), cyanation of aryl halides (Rosenmund–von Braun reaction), Hurtley reaction and intermolecular oxidative cyclization of haloalkynes [41

• . The Pd-catalyzed Sonogashira reaction has successfully constructed arylated internal alkynes that are important intermediates in organic synthesis, molecular electronics and polymers [56]. C–N bond forming reactions between aryl halides and amines/amides/sulfonamides have been extensively studied in

Synthesis of 9-O-arylated berberines via copper-catalyzed C_Ar–O coupling reactions

• Qiaoqiao Teng,
• Xinhui Zhu,
• Qianqian Guo,
• Weihua Jiang,
• Jiang Liu and
• Qi Meng

Beilstein J. Org. Chem. 2019, 15, 1575–1580, doi:10.3762/bjoc.15.161

• temperature, during which 9-O-methyl cleavage occurs. The resulting berberrubine (BBRB) then acts as a good precursor to 9-O-substituted derivatives through nucleophilic substitution reactions with alkyl halides (Scheme 1). By this route, not only long-chain alkyl substituents were installed, but also more

• structure. Considering the great abundance of aryl halides, the method allows the preparation of more diverse BBR derivatives in the future. The relevant biological study of the newly synthesized compounds is currently underway in our laboratory. Synthetic pathway of 9-O-R BBR. Resonance of berberrubine

Borylation and rearrangement of alkynyloxiranes: a stereospecific route to substituted α-enynes

• Ruben Pomar Fuentespina,
• José Angel Garcia de la Cruz,
• Gabriel Durin,
• Victor Mamane,
• Jean-Marc Weibel and
• Patrick Pale

Beilstein J. Org. Chem. 2019, 15, 1416–1424, doi:10.3762/bjoc.15.141

• coupling reactions of either terminal or organometallic alkynes with vinyl halides or of alkynyl halides with vinylic organometallics [20]. However, both routes may lead to mixtures of stereoisomers and synthetic approaches to stereodefined substituted α-enynes remain scarce and thus still represent a

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• , and potassium hydroxide as base in DMSO (Scheme 1). This method has been previously used for the synthesis of symmetrical diaryl selenides from aryl halides [28]. Attempts to use the corresponding 3,3’-dibromo-2,2’-bithiophene as starting material for the synthesis of either DTS 2 with the same

Enantioselective Diels–Alder reaction of anthracene by chiral tritylium catalysis

• Qichao Zhang,
• Jian Lv and
• Sanzhong Luo

Beilstein J. Org. Chem. 2019, 15, 1304–1312, doi:10.3762/bjoc.15.129

• tritylium salts with a chiral weakly coordinating metal-based phosphate anion could facilitate the asymmetric catalytic Diels–Alder reaction. To implement this strategy, different trityl phosphates or halides, Lewis acids, chiral metal phosphate and their combinations were examined in the model reaction of

Alkylation of lithiated dimethyl tartrate acetonide with unactivated alkyl halides and application to an asymmetric synthesis of the 2,8-dioxabicyclo[3.2.1]octane core of squalestatins/zaragozic acids

• Herman O. Sintim,
• Hamad H. Al Mamari,
• Hasanain A. A. Almohseni,
• Younes Fegheh-Hassanpour and
• David M. Hodgson

Beilstein J. Org. Chem. 2019, 15, 1194–1202, doi:10.3762/bjoc.15.116

• LDA and reaction at −78 °C during 12–72 h with a range of alkyl halides, including non-activated substrates, to give single diastereomers (at the acetonide) of monoalkylated tartrates 17, 24, 33a–f, 38a,b, 41 of R,R-configuration, i.e., a stereoretentive process (13–78% yields). Separable trans

• (e.g., 7, Scheme 2) was originally reported by Seebach and co-workers for ‘activated’ (allylic, benzylic) alkyl halides [17][18][19]. If an alkylated tartrate 9 could be accessed from a silyloxy-substituted alkyl iodide 8 and subsequently oxidised (for example via a second tartrate enolate) with

• work, which concluded that only especially reactive halides (methyl, benzylic, allylic) were feasible electrophiles; with iodoethane, 1-iodo-2-methylpropane and chloromethoxymethane no alkylation products were formed [17][18][19]. Given these rather discouraging observations in the context of our

Insertion of [1.1.1]propellane into aromatic disulfides

• Robin M. Bär,
• Gregor Heinrich,
• Martin Nieger,
• Olaf Fuhr and
• Stefan Bräse

Beilstein J. Org. Chem. 2019, 15, 1172–1180, doi:10.3762/bjoc.15.114

• nucleophiles also proceeds through a radical mechanism [14][15]. The reaction with alkyl halides, initially described by Michl et al. [16], has recently been further investigated by Anderson et al. (Scheme 1) [17]. Both groups showed that the BCP halide can be lithiated to further modify the products. The

Synthesis of aryl cyclopropyl sulfides through copper-promoted S-cyclopropylation of thiophenols using cyclopropylboronic acid

• Emeline Benoit,
• Ahmed Fnaiche and
• Alexandre Gagnon

Beilstein J. Org. Chem. 2019, 15, 1162–1171, doi:10.3762/bjoc.15.113

• ). For instance, the proton alpha to the sulfur can be removed by a strong base such as butyllithium, resulting in the cyclopropyllithium species 2. This carbanion can then react with alkyl halides to provide the corresponding alkylated species 3 which can then be opened up by treatment with mercuric

Design of a double-decker coordination cage revisited to make new cages and exemplify ligand isomerism

• Sagarika Samantray,
• Sreenivasulu Bandi and
• Dillip K. Chand

Beilstein J. Org. Chem. 2019, 15, 1129–1140, doi:10.3762/bjoc.15.109

• of Pd(NO3)2 with L1 at a 1:2 or 3:4 ratios afforded [Pd(L1)2](NO3)2 (3a) and [(NO3)2@Pd3(L1)4](NO3)4 (4a), respectively. The encapsulated NO3– ions of 4a undergo anion exchange with halides (F–, Cl– and Br– but not with I–) to form [(X)2@Pd3(L1)4](NO3)4 5a–7a. The coordination behaviour of ligand L1

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

• Shahien Shahsavari,
• Dhananjani N. A. M. Eriyagama,
• Bhaskar Halami,
• Vagarshak Begoyan,
• Marina Tanasova,
• Jinsen Chen and
• Shiyue Fang

Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108

• , alkyl halides, α-halocarbonyls, vinylpurines, methides and maleimides cannot or are difficult to be incorporated into ODNs, or cannot be installed at the desired locations in the ODNs. For example, to synthesize oligos that contain the epigenetically modified 5-formylcytosine, the aldehyde group had to

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• reaction of propiolic acid and aryl halides [78]. Furthermore, the authors have been able to carry out the reaction in a sequential manner starting from propiolic acid and aryl iodides in the presence of caesium carbonate and a palladium catalyst. Next, addition of 2-iodobenzoic acid and ammonium acetate

Heck- and Suzuki-coupling approaches to novel hydroquinone inhibitors of calcium ATPase

• Robert J. Kempton,
• Taylor A. Kidd-Kautz,
• Soizic Laurenceau and
• Stefan Paula

Beilstein J. Org. Chem. 2019, 15, 971–975, doi:10.3762/bjoc.15.94

• , a BHQ analogue and active SERCA inhibitor containing a side chain terminating in a leucine moiety. Results and Discussion The starting materials for the syntheses were the halides 4a,b (Scheme 1). Bromide 4a is commercially available. We investigated several ways to prepare the corresponding iodide

• ) suggesting the presence of a small amount of the 3-tert-butyl isomer. The corresponding iodo analogue 5b was prepared following the procedure of Hayashi [14]. Although both halides 5a and 5b were now available to us, subsequent experiments determined that the iodo analogue offered us no advantage over the

Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests

• Fangfang Pan,
• Mohadeseh Dashti,
• Michael R. Reynolds,
• Kari Rissanen,
• John F. Trant and
• Ngong Kodiah Beyeh

Beilstein J. Org. Chem. 2019, 15, 947–954, doi:10.3762/bjoc.15.91

• high Z’-value structure. Disorder is not inherently a feature of a poor structure, disorder instead indicates the complexity of the dynamic solution state. Solving it, however, remains a challenge. N-Alkylammonium resorcinarene halides (NARXs) have been extensively studied in our groups as multidentate

• groups. Halides such as chloride and bromides can have high coordination numbers and as such can simultaneously be involved in both HB and XB to form ordered assemblies [32][33]. When the already hydrogen-bonded halides in NARXs are involved in XB, changes in the 1H NMR chemical shifts of the –OH and

Towards the preparation of synthetic outer membrane vesicle models with micromolar affinity to wheat germ agglutinin using a dialkyl thioglycoside

• Dimitri Fayolle,
• Nathalie Berthet,
• Bastien Doumeche,
• Olivier Renaudet,
• Peter Strazewski and
• Michele Fiore

Beilstein J. Org. Chem. 2019, 15, 937–946, doi:10.3762/bjoc.15.90

• ]. Some of them have been obtained by coupling protected glycosyl thiolates and n-alkyl halides [14][15][16]. Moreover, mechanochemical thioglycosylation of glycosyl acetates was used for the synthesis of n-alkyl 1-thio-α--glycosides as carbohydrate mesogens [17]. Unfortunately, the preparation of alkyl

Synthesis and SAR of the antistaphylococcal natural product nematophin from Xenorhabdus nematophila

• Frank Wesche,
• Hélène Adihou,
• Thomas A. Wichelhaus and
• Helge B. Bode

Beilstein J. Org. Chem. 2019, 15, 535–541, doi:10.3762/bjoc.15.47

• aluminium chloride (AlCl3) in DCM to give compounds 14 and 21. Subsequent reduction was achieved with triethylsilane (Et3SiH) in TFA to give 15 and 22. For the synthesis of the primary amine, halides 15 and 22 were converted in a Gabriel synthesis with potassium phthalimide in DMF to the appropriate

Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Katarzyna Urbaniak,
• Marcin Jasiński,
• Vladyslav Bakhonsky,
• Peter R. Schreiner and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2019, 15, 497–505, doi:10.3762/bjoc.15.43

• -oxide using two different alkyl halides (R1X and R2X; R1, R2 = Me, Et, n-Bu, or allyl) as alkylating agents, leading to non-symmetric 1,3-dialkoxyimidazolium salts, was also reported [26]. In the present study, imidazole N-oxides 7 bearing either an adamantyloxy or adamantyl moiety at N(1) were smoothly

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• available 2,6-dichloropurine (1a) by subsequent alkylation of the N(9) position and azido group introduction in C(2) and C(6) positions. The N(9) position of purine was alkylated in two different ways: 1) using alkyl halides in the presence of a strong base, and 2) using alcohols under Mitsunobu conditions

• . In the first approach (method A, Scheme 1), the purine was deprotonated with a base (NaH or K2CO3) and alkylated with alkyl halides such as 1-iodoheptane, 1-bromononane and 1-bromododecane. The main disadvantages of this approach are suboptimal yields, which varied from 48% to 52%, and long reaction

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

• adopted to access NR+ and NMN. 2.1. Glycosylation of nicotinamide As mentioned above, glycosylation of Nam may be performed either by using halosugars, i.e., 2,3,5-tri-O-acyl-D-ribofuranosyl halides, or by applying 1,2,3,5-tetra-O-acyl-D-ribofuranoses. The latter fully acylated sugars require different

• reaction conditions for the glycosylation of nicotinamide. Historically, 2,3,5-tri-O-acyl-D-ribofuranosyl halides were used first (so called the halo route) and will be considered in the first place. 2.1.1. Glycosylation with 2,3,5-tri-O-acylribofuranosyl halides: The first works on the chemical synthesis

Study on the regioselectivity of the N-ethylation reaction of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide

• Pedro N. Batalha,
• Luana da S. M. Forezi,
• Maria Clara R. Freitas,
• Nathalia M. de C. Tolentino,
• Ednilsom Orestes,
• José Walkimar de M. Carneiro,
• Fernanda da C. S. Boechat and
• Maria Cecília B. V. de Souza

Beilstein J. Org. Chem. 2019, 15, 388–400, doi:10.3762/bjoc.15.35

• -4-oxoquinoline derivative, the aliphatic nucleophilic substitution reaction can be employed, in which the 4-oxoquinoline nucleus acts as an azanucleophile, reacting with different alkyl halides. This reaction leads to products with high yields, and no byproducts are isolated. In this paper we

Metal-free C–H mercaptalization of benzothiazoles and benzoxazoles using 1,3-propanedithiol as thiol source

• Yan Xiao,
• Bing Jing,
• Xiaoxia Liu,
• Hongyu Xue and
• Yajun Liu

Beilstein J. Org. Chem. 2019, 15, 279–284, doi:10.3762/bjoc.15.24

• activity against Candida albicans and Candida tropicalis [8] and 2-mercapto-1,3-benzothiol and its derivatives exhibit inhibitory effects against thyroid peroxidase [9]. (Hetero)aryl thiols are often prepared from the corresponding halides through direct nucleophilic substitution [10][11][12] or metal

• reaction conditions were obtained as follows: benzothiazole (1.0 mmol), 1,3-propanedithiol (2.0 equiv), KOH (5.0 equiv), DMSO (3 mL), 130 °C, 12 h. We further investigated several common thiol surrogates, which are often used in the C–H mercaptalization of aryl halides. Under the optimized conditions, 1

Oxidative radical ring-opening/cyclization of cyclopropane derivatives

• Yu Liu,
• Qiao-Lin Wang,
• Zan Chen,
• Cong-Shan Zhou,
• Bi-Quan Xiong,
• Pan-Liang Zhang,
• Chang-An Yang and
• Quan Zhou

Beilstein J. Org. Chem. 2019, 15, 256–278, doi:10.3762/bjoc.15.23

• halides in excellent yields (path VII in Scheme 18). Similarly, the radical reaction of MCPs 1 with the RFTMS/CsF/PhI(OAc)2 gave homoallylic acohol esters in moderate to good yields (path VI in Scheme 18). Oxidative radical ring-opening and cyclization of cyclopropyl olefins In 2016, Li’s group reported a

Reactions of 3-(p-substituted-phenyl)-5-chloromethyl-1,2,4-oxadiazoles with KCN leading to acetonitriles and alkanes via a non-reductive decyanation pathway

• Akın Sağırlı and
• Yaşar Dürüst

Beilstein J. Org. Chem. 2018, 14, 3011–3017, doi:10.3762/bjoc.14.280

• that are generally obtained by the reaction of benzyl halides with appropriate cyanating agents such as KCN [14], TMSCN [15], K4(Fe(CN)6 [16]. Deprotonation of the α-carbon (adjacent to nitrile) by strong bases, especially lithiated ones, resulted in an anionic species that easily undergoes a

• substitution reaction with various alkyl halides to afford mono-, di- or trialkylated acetonitriles [17]. Most recently, Strzalko and co-workers disclose mono and dialkylation of the benzylic carbon of phenylacetonitrile with a poor selectivity by benzyl and methyl halides in the presence of LiHMDS, LDA or n

Copper(I)-catalyzed tandem reaction: synthesis of 1,4-disubstituted 1,2,3-triazoles from alkyl diacyl peroxides, azidotrimethylsilane, and alkynes

• Muhammad Israr,
• Changqing Ye,
• Munira Taj Muhammad,
• Yajun Li and
• Hongli Bao

Beilstein J. Org. Chem. 2018, 14, 2916–2922, doi:10.3762/bjoc.14.270

• the azidation of organic halides, such as aliphatic halides, vinyl halides, or aromatic halides with sodium azide [24][25][26][27]. Organic triflates [28] and organic boronic acids [29][30][31] can also be used as alternative precursors for organic azides, when reacted with sodium azide. However

• functionality of organic azide source. Moreover, as one of the most commonly appearing compounds in nature, carboxylic acids have rarely been directly used as the organic azide precursors for CuAAC reactions, considering the frequent involvement of organic halides. Thus, new methods with non or less toxic